Surface-coated cutting tool with hard coating layer that exhibits excellent chipping resistance and manufacturing method thereof

ABSTRACT

In a hard coating layer that contains at least any of a layer of a complex nitride or a complex carbonitride (composition formula: (Ti 1-x Al x )(C y N 1-y )) of chemically-vapor-deposited Ti and Al, a layer of a complex nitride or a complex carbonitride (composition formula: (Ti 1-α-β Al α Mr β )(C γ Ni 1-γ )) of Ti, Al, and Me, and a layer of a complex nitride or a complex carbonitride (composition formula: (Cr 1-p Al p )(C q N 1-q ) of Cr and Al in a surface-coated cutting tool, some crystal grains that form the layer of a complex nitride or a complex carbonitride have cubic structures, and a predetermined average crystal grain misorientation and inclined angle frequency distribution are present in the crystal grains that have cubic structures.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This application is a U.S. National Phase Application under 35 U.S.C. § 371 of International Patent Application No. PCT/JP2016/082353 filed on Oct. 31, 2016 and claims the benefit of Japanese Patent Applications No. 2015-214520, filed Oct. 30, 2015, No. 2015-214524, filed Oct. 30, 2015, No. 2015-214527, filed Oct. 30, 2015, and No. 2016-211414, filed Oct. 28, 2016, all of which are incorporated herein by reference in their entireties. The International Application was published in Japanese on May 4, 2017 as International Publication No. WO/2017/073789 under PCT Article 21(2).

FIELD OF THE INVENTION

The present invention relates to a surface-coated cutting tool (hereinafter, referred to as “coated tool”) with a hard coating layer that has excellent chipping resistance and exhibits excellent cutting performance in use over a long period of time in a high-speed intermittent cutting of alloy steel or the like during which high temperature is generated and impact loads are exerted on a cutting edge.

BACKGROUND OF THE INVENTION

In the related art, a coated tool in which a Ti—Al-based or Cr—Al-based complex nitride layer is coated as a hard coating layer on a surface of a tool body that is formed of a tungsten carbide (hereinafter, referred to as WC)-based cemented carbide, titanium carbonitride (hereinafter, referred to as TiCN)-based cermet, or a cubic crystal boron nitride (hereinafter, referred to as cBN)-based ultra-high-pressure sintered body (hereinafter, collectively referred to as a tool body) by a physical vapor deposition method is typically known, and it is known that this exhibits excellent wear resistance.

However, since the coated tool in the related art, in which the Ti—Al-based or Cr—Al-based complex nitride layer is coated, has relatively excellent wear resistance while abnormal wear such as chipping tends to occur in a case in which the coated tool is used under high-speed intermittent cutting conditions, various suggestions have been made to improve the hard coating layer.

For example, Japanese Unexamined Publication No. 2012-20391 discloses a surface-coated cutting tool that can obtain excellent wear resistance and fracture resistance by a configuration in which a hard coating layer is formed on a surface of a tool body, in which the hard coating layer is formed of one layer or a plurality of layers, T1<T2 is satisfied where T1 represents the thickness of the thinnest portion of the hard coating layer at a ridge line portion of a cutting edge, and T2 represents the thickness at a location of 1 mm away from the ridge line of the cutting edge in a rake face direction, Da and Db are inside specific numerical ranges where a represents a location that is a distance Da in the rake face direction from the ridge line of the cutting edge on the surface of the hard coating layer, and b represents a location that is a distance Db in a flank face direction therefrom, and unevenness in a crystal orientation of crystal grains that form the hard coating layer is equal to or greater than 5 degrees and less than 10 degrees in a region corresponding to 10% or more of a region E that occupies the thickness 0.1T1 to 0.9T1 from the surface of the hard coating layer from the location a to the location b.

In addition, Japanese Unexamined Publication No. 2000-144376 discloses that a film with excellent wear resistance, seizure resistance, and oxidation resistance, with a low friction coefficient, and excellent sliding properties is obtained by forming a complex hard film that is formed of at least two kinds of metal nitride from among nitrides of Cr, Ti, Al, and V on the surface of a tool body and setting an intensity ratio I(111)/I(200) between X-ray diffraction peaks I(111) and I(200) of a (111) plane and a (200) plane that are obtained by X-ray diffraction for the hard film to be a value from 3 to 6.

However, there is a disclosure that TiAlN is deposited as the hard coating layer in the aforementioned coated tool while there is neither disclosure nor indication that the content ratio x of Al is set to be equal to or greater than 0.65.

From such a viewpoint, a technology of increasing the content ratio x of Al to about 0.9 by forming the hard coating layer by a chemical vapor deposition method has also been proposed.

For example, Japanese Unexamined Publication No. 2011-516722 describes that it is possible to deposit a (Ti_(1-x)Al_(x))N layer in which the value of the content ratio x of Al ranges from 0.65 to 0.95 by performing chemical vapor deposition within a temperature range of 650 to 900° C. in mixed reaction gas of TiCl₄, AlCl₃, and NH₃. However, since an Al₂O₃ layer is further applied onto the (Ti_(1-x)Al_(x))N layer for the purpose of enhancing a thermal insulation effect, it is not obvious in this document how the formation of the (Ti_(1-x)Al_(x))N layer in which the value of the content ratio x of Al is increased up to 0.65 to 0.95 affects cutting performance.

In addition, Japanese Unexamined Publication No. 2011-513594, for example, proposes that heat resistance and fatigue strength of a coated tool are improved by coating, as an outer layer, a (Ti_(1-x)Al_(x))N layer (where an atomic ratio of x ranges from 0.65 to 0.90) with a cubic structure or a hexagonal structure by a chemical vapor deposition method on a TiCN layer and an Al₂O₃ layer that are inner layers and applying compressive stress of 100 to 1100 MPa to the outer layer.

For example, Japanese Unexamined Publication No. 2006-82207 discloses a surface-coated cutting tool that includes a tool body and a hard coating layer formed on the body thereof, in which wear resistance and oxidation resistance of the hard coating layer are significantly improved due to either or both Al and Cr elements, at least one kind of element selected from a group consisting of Group 4a elements, Group 5a elements, and Group 6a elements in the periodic table and Si, a compound that is formed from at least one kind of element selected from a group consisting of carbon, nitrogen, oxygen, and boron, and chlorine being contained.

For example, Japanese Unexamined Publication No. 2014-208394 proposes that the adhesion strength between a lower layer and an upper layer may be improved, and chipping resistance and wear resistance may thus be improved by providing a hard coating layer that is formed of the lower layer, an intermediate layer, and an upper layer on a surface of a tool body such that the lower layer has a predetermined average layer thickness and is formed of a TiAl compound that has a cubic structure formed of one layer or two or more layers from among a Ti_(1-x)Al_(x)N layer, a Ti_(1-x)Al_(x)C layer, and a Ti_(1-x)Al_(x)CN layer (X is the content ratio (atomic ratio) of Al and satisfies 0.65≤X≤0.95), the intermediate layer has a predetermined average layer thickness and is formed of a CrAl compound that has a cubic structure formed of one layer or two or more layers from among a Cr_(1-Y)Al_(Y)N layer, a Cr_(1-Y)Al_(Y)C layer, and a Cr_(1-Y)Al_(Y)CN layer (Y is the content ratio (atomic ratio) of Al and satisfies 0.60≤Y≤0.90), and upper layer is formed of Al₂O₃ that has a predetermined average layer thickness, in order to improve the chipping resistance and the wear resistance in a high-speed intermittent cutting of stainless steel, a Ti alloy, or the like.

In addition, Japanese Unexamined Publication No. 2014-198362 proposes that the adhesion strength between a lower layer and an upper layer may be improved, and the upper layer be formed of an Al₂O₃ layer that has fine pores with a predetermined pore diameter and pore density to alleviate mechanical and thermal impacts, thereby improving chipping resistance and wear resistance, by providing a hard coating layer that is formed of the lower layer, an intermediate layer, and the upper layer on a surface of a tool body such that the lower layer is formed of a Ti compound that has a cubic crystal structure formed of one layer or two or more layers from among a Ti_(1-x)Al_(x)N layer, a Ti_(1-x)Al_(x)C layer, and a Ti_(1-x)Al_(x)CN layer (X is an atomic ratio that indicates a content portion of Al and satisfies 0.65≤X≤0.95) with a predetermined average layer thickness per layer, the intermediate layer is formed of a Cr compound that has a cubic crystal structure formed of one layer or two or more layers from among a Cr_(1-Y)Al_(Y)N layer, a Cr_(1-Y)Al_(Y)C layer, and a Cr_(1-Y)Al_(Y)CN layer (Y is an atomic ratio that indicates the content ratio of Al and satisfies 0.60≤Y≤0.90), and the upper layer is formed of Al₂O₃ that has fine pores with a predetermined pore diameter and pore density and an average layer thickness, in order to improve the chipping resistance and the wear resistance in a high-speed intermittent cutting of a heat-resistant alloy such as precipitation hardening stainless steel and an Inconel alloy.

Further, Japanese Unexamined Publication No. 2009-56539 proposes that the high-temperature strength of an (Al_(1-X)Cr_(X))N layer may be improved, and fracture resistance of a hard coating layer in a heavy-duty cutting may thus be improved by providing the hard coating layer formed of the (Al_(1-X)Cr_(X))N layer (where X is an atomic ratio and satisfies X=0.3 to 0.6) on the surface of the tool body, and forming a crystal orientation and a constituent atom shared lattice point distribution form such that in an inclined angle frequency distribution graph created by measuring inclined angles formed by normal lines of {100} planes with respect to a normal line of a polished surface as a surface of the tool body, the highest peak is present in an inclined angle section from 30 to 40 degrees and the total frequencies thereof accounts for equal to or greater than 60% with respect to the entire frequencies, and in a constituent atom shared lattice point distribution graph created by measuring inclined angles formed by normal lines of {112} planes with respect to the normal line of the polished surface as a surface, the highest peak is present at Σ3, and the distribution ratio thereof is equal to or greater than 50% with respect to the entire frequencies, in order to enhance fracture resistance of the hard coating layer in heavy-duty cutting of steel or cast iron, in which a large load acts on the cutting edge.

Problems to be Solved by the Invention

Requirements for saving power and energy in a cutting have increased in recent years, which has been accompanied by trends to a higher speed and efficiency in the cutting, and a coated tool has been required to have higher abnormal damage resistance such as chipping resistance, fracture resistance, and peeling resistance and also to have excellent wear resistance for use over a long period of time.

However, since the coated tools described in Japanese Unexamined Publications No. 2012-20391 and No. 2000-144376 described above do not take an increase in the content ratio x of Al in the hard coating layer formed of the (Ti_(1-x)Al_(x))N layer into consideration, there is a problem that it is not possible to state that the wear resistance and the chipping resistance are sufficient in a case in which the coated tool is used in high-speed intermittent cutting of alloy steel.

Meanwhile, since in the (Ti_(1-x)Al_(x))N layer deposited by the chemical vapor deposition method described in Japanese Unexamined Publication No. 2011-516722 described above, the content ratio x of Al can be increased and cubic structures are formed, it is possible to obtain a hard coating layer with predetermined hardness and excellent wear resistance. However, there is a problem that toughness is poor.

Furthermore, since the coated tool described in Japanese Unexamined Publication No. 2011-513594 described above has poor toughness although it has predetermined hardness and excellent wear resistance, there is a problem that abnormal damages, such as chipping, fracture, and peeling tend to occur and it is not possible to state that the coated tool exhibits satisfactory cutting performance in a case in which the coated tool is used in a high-speed intermittent cutting or the like of alloy steel.

In addition, although the coated tool described in Japanese Unexamined Publication No. 2006-82207 described above is intended to improve wear resistance and oxidation resistant properties, there is a problem that chipping resistance is not sufficient under cutting conditions with impacts, such as high-speed intermittent cutting.

In addition, since the coated tools described in Japanese Unexamined Publications No. 2014-208394 and No. 2014-198362 described above do not have sufficient strength and hardness for a CrAl compound and Cr compound themselves although the adhesion strength between the lower layer and the upper layer is improved and chipping resistance is enhanced by causing the CrAl compound and the Cr compound to be interposed as the intermediate layer in the hard coating layer, it is not possible to state that chipping resistance and wear resistance are sufficient in a case in which the coated tool is used in a high-speed intermittent cutting.

In addition, since the coated tool described in Japanese Unexamined Publication No. 2009-56539 described above also do not have sufficient strength and hardness for the (Ti_(1-x)Al_(x))N layer although it is possible to improve the strength of the hard coating layer, and as a result, it is possible to improve chipping resistance and fracture resistance by adjusting the content ratio of Cr in the hard coating layer formed of (Ti_(1-x)Al_(x)) N and controlling a crystal orientation and a constituent atom shared lattice point distribution form, there is a problem that the coated tool may not exhibit excellent chipping resistance and wear resistance in use over a long period of time and a tool life for high-speed intermittent cutting of alloy steel may be short.

Thus, a technical problem to be solved by the present invention, namely an object of the present invention is to provide a coated tool that has excellent toughness and exhibits excellent chipping resistance and wear resistance in use over a long period of time even in a case in which the coated tool is used in high-speed intermittent cutting of carbon steel, alloy steel, cast iron, or the like.

SUMMARY OF THE INVENTION Means for Solving the Problems

Thus, the present inventors has gained the following knowledge as a result of extensive research to improve chipping resistance and wear resistance of a coated tool in which a hard coating layer that contains at least a complex nitride or a complex carbonitride of Ti and Al (hereinafter, also referred to as “(Ti, Al)(C, N)” or “(Ti_(1-x)Al_(x))(C_(y)N_(1-y))” in some cases) and a complex nitride or a complex carbonitride of Cr and Al (hereinafter, also referred to as “(Cr, Al)(C, N) or (Cr_(1-p)Al_(p))(C_(q)N_(1-q))” in some cases) is deposited, from the aforementioned viewpoint.

That is, a hard coating layer that includes at least one (Ti_(1-x)Al_(x))(C_(y)N_(1-y)) layer and one (Cr_(1-p)Al_(p))(C_(q)N_(1-q)) layer and has a predetermined average layer thickness has high wear resistance in a case in which the (Ti_(1-x)Al_(x))(C_(y)N_(1-y)) layer and the (Cr_(1-p)Al_(p))(C_(q)N_(1-q)) layer are formed into columnar shapes in a direction perpendicular to the tool body. On the other hand, toughness of the (Ti_(1-x)Al_(x))(C_(y)N_(1-y)) layer and the (Cr_(1-p)Al_(p))(C_(q)N_(1-q)) layer decreases as anisotropy of the (Ti_(1-x)Al_(x))(C_(y)N_(1-y)) layer and the (Cr_(1-p)Al_(p))(C_(q)N_(1-q)) layer increases. As a result, chipping resistance and fracture resistance decrease, sufficient wear resistance cannot be exhibited in use over a long period of time, and it is not possible to state that the tool life is satisfactory.

Thus, the present inventors have found new knowledge that it is possible to successfully improve both hardness and toughness by causing strain in crystal grains that have NaCl-type face-centered cubic structures (hereinafter, also simply referred to as “cubic structures”) and to improve chipping resistance and fracture resistance of the hard coating layer as a result on the basis of the following completely new ideas (1) to (3), as a result of intensive studies regarding the (Ti_(1-x)Al_(x))(C_(y)N_(1-y)) layer and the (Cr_(1-p)Al_(p))(C_(q)N_(1-q)) layer that form the hard coating layer.

(1) An idea that the (Ti_(1-x)Al_(x))(C_(y)N_(1-y)) layer that is a complex nitride or a complex carbonitride of Ti and Al contains crystal grains that have NaCl-type face-centered cubic structures and average crystal grain misorientations of the crystal grains that have cubic structures are set to be equal to or greater than 2 degrees.

(2) An idea that the hard coating layer is caused to contain one kind of element (hereinafter, referred to as “Me” selected from Si, Zr, B, V, and Cr, the (Ti_(1-α-β)Al_(α))(C_(γ)N_(1-γ)) layer which is a complex nitride or a complex carbonitride of Ti, Al, and Me contains crystal grains that have NaCl-type face-centered cubic structures, and the average crystal grain misorientations of the crystal grains that have a cubic structure are set to be equal to or greater than 2 degrees.

(3) An idea that the (Cr_(1-p)Al_(p))(C_(q)N_(1-q)) layer that is a complex nitride or a complex carbonitride of Cr and Al contains crystal grains that have NaCl-type face-centered cubic structure, and the average crystal grain misorientations of the crystal grains that have a cubic structures are set to be equal to or greater than 2 degrees.

Further, the present inventors have found new knowledge that a higher ratio of the {111} orientation on the side of the film surface than on the side of the surface of the tool body in the columnar-shaped crystal grain causes further improvement in toughness.

Specifically, the present inventors have found that in a case in which the hard coating layer:

(1) contains at least a layer of a complex nitride or a complex carbonitride of Ti and Al and is represented by a composition formula: (Ti_(1-x)Al_(x))(C_(y)N_(1-y)), particularly, and the average content ratio x_(avg) of Al with respect to the total amount of Ti and Al and the average content ratio of C with respect to the total amount of C and N (where both x_(avg) and y_(avg) are atomic ratios) satisfy 0.60≤x_(avg)≤0.95 and 0≤y_(avg≤)0.005, respectively, it is possible to cause strain in crystal grains that have a cubic structures when some crystal grains that form the layer of a complex nitride or a complex carbonitride have cubic structure, and crystal grains with average crystal grain misorientations of equal to or greater than 2 degrees are present at an area ratio of 20% or greater in the layer of a complex nitride or a complex carbonitride in a case in which the crystal orientations of the crystal grains are analyzed in a vertical sectional direction by using an electron backscatter diffraction apparatus, and the average crystal grain misorientations of the individual crystal grains are obtained;

(2) contains at least a layer of a complex nitride or a complex carbonitride of Ti, Al, and Me (where Me is one kind of element selected from Si, Zr, B, V, and Cr) and is represented by a composition formula: (Ti_(1-α-β)Al_(α)Me_(β))(C_(γ)N_(1-γ)), particularly, when an average content ratio α_(avg) of Al with respect to the total amount of Ti, Al, and Me, an average content ratio β_(avg) of Me with respect to the total amount of Ti, Al and Me, and an average content ratio γ_(avg) of C with respect to the total amount of C and N (where all of α_(avg), β_(avg) and γ_(avg) are atomic ratios) satisfy 0.60≤α_(avg), 0.005≤β_(avg)≤0.10, 0≤γ_(avg)≤0.005, and 0.605≤α_(avg)+β_(avg)≤0.95, respectively, it is possible to cause strain in crystal grains that have cubic structures when some crystal grains that form the layer of a complex nitride or a complex carbonitride have cubic structures and crystal grains with average crystal grain misorientations of equal to or greater than 2 degrees are present at an area ratio of 20% or greater in the layer of a complex nitride or a complex carbonitride in a case in which the crystal orientations of the crystal grains are analyzed in the vertical sectional direction by using an electron backscatter diffraction apparatus, and the average crystal grain misorientations of the individual crystal grains are obtained; and

(3) contains at least a layer of a complex nitride or a complex carbonitride of Cr and Al and is represented by a composition formula: (Cr_(1-p)Al_(p))(C_(q)N_(1-q)), particularly, when an average content ratio p_(avg) of Al with respect to the total amount of Cr and Al and an average content ratio q_(avg) of C with respect to the total amount of C and N (where both p_(avg) and q_(avg) are atomic ratios) satisfy 0.70≤p_(avg≤)0.95 and 0≤q_(avg)≤0.005, respectively, it is possible to cause strain in crystal grains that have cubic structures when some crystal grains that form the layer of a complex nitride or a complex carbonitride have cubic structures, and crystal grains with average crystal grain misorientations of equal to or greater than 2 degrees are present at an area ratio of 20% or greater in the layer of a complex nitride or a complex carbonitride in a case in which the crystal orientations of the crystal grains are analyzed in the vertical sectional direction by using an electron backscatter diffraction apparatus and the average crystal grain misorientations of the individual crystal grains are obtained, and

(4) further, in any of (1) to (3) described above, toughness is improved by setting a higher ratio of the {111} orientation of the crystal grains on the side of the film surface than on the side of the surface of the tool body.

As a result, the present inventors have found that a cutting tool with such a hard coating layer formed thereon has improved chipping resistance and fracture resistance and exhibits excellent wear resistance over a long period of time.

Further, the (Ti_(1-x)Al_(x))(C_(y)N_(1-y)) layer, the (Ti_(1-α-β)Al_(α)Me_(β))(C_(γ)N_(1-γ)) layer, and the (Cr_(1-p)Al_(p))(C_(q)N_(1-q)) layer with the aforementioned configurations can be formed by the following chemical vapor deposition methods, in which a reaction gas composition is periodically changed on the surface of the tool body, for example.

(1) Concerning (Ti_(1-x)Al_(x))(C_(y)N_(1-y)) Layer

A gas group A consisting of NH₃, N₂, and H₂ and a gas group B consisting of TiCl₄, Al(CH₃)₃, AlCl₃, N₂, and H₂ are supplied to a reactor of a chemical vapor deposition reaction apparatus which is to beused from separate gas supply tubes. The gas group A and the gas group B are supplied into the reaction apparatus such that the gas flows over time intervals with a specific cycle for a shorter time than the cycle and a phase difference in a shorter time than the gas supply time occurs in the gas supply of the gas group A and the gas group B, thereby temporarily changing the reaction gas composition on the surface of the tool body among the gas group A, mixed gas of the gas group A and the gas group B, and the gas group B. Incidentally, there is no need to introduce a gas discharge process over a long time intended to strictly substitute the gas in the present invention. Therefore, it is also possible to realize a gas supply method by rotating a gas supply port, rotating a tool body, or reciprocating the tool body to temporarily change the reaction gas composition on the surface of the tool body among mixed gas mainly containing the gas group A (first reaction gas), mixed gas of the gas group A and the gas group B (second reaction gas), and mixed gas mainly containing the gas group B (third reaction gas).

The (Ti_(1-x)Al_(x))(C_(y)N_(1-y)) layer with a predetermined target layer thickness is formed by performing a thermal CVD method on the surface of the tool body for a predetermined time by setting the reaction gas composition (% by volume with respect to the total of the gas group A and the gas group B) to NH₃: 1.0 to 1.5%, N₂: 1.0 to 2.0%, and H₂: 55 to 60% as the gas group A, AlCl₃: 0.6 to 0.9%, TiCl₄: 0.2 to 0.3%, Al(CH₃)₃: 0 to 0.5%, N₂: 12.5 to 15.0%, and H₂: the remaining amount as the gas group B, for example, under conditions of a reaction atmosphere pressure: 4.5 to 5.0 kPa, a reaction atmosphere temperature: 700 to 900° C., a supply cycle: 1 to 5 seconds, a gas supply time per cycle: 0.15 to 0.25 seconds, and a supply phase difference between the gas group A and the gas group B: 0.10 to 0.20 seconds.

Then, local strain in crystal lattice is formed in the crystal grains due to introduction of local unevenness in composition, dislocation, and point defect, and it is possible to change degrees of {111} orientation of the crystal grains on the side of the surface of the tool body and on the side of the film surface, by supplying the gas group A and the gas group B such that a difference occurs between a time at which the gas group A reaches the surface of the tool body and a time at which the gas group B reaches the surface of the tool body, setting NH₃: 1.0 to 1.5% as a nitrogen raw material gas in the gas group A, and setting AlCl₃: 0.6 to 0.9%, TiCl₄: 0.2 to 0.3%, and Al(CH₃)₃: 0 to 0.5% as metal chloride raw materials or carbon raw materials in the gas group B as described above. It has been found that as toughness is significantly improved while wear resistance is maintained as a result. The present inventors have found that as a result, fracture resistance and chipping resistance, in particular, are improved while wear resistance is maintained, and the hard coating layer can exhibit an excellent cutting performance in use for a long period of time even in a case in which the coated tool is used in a high-speed intermittent cutting of alloy steel or the like in which an intermittent and impact load are exterted on the cutting edge.

(2) Concerning (Ti_(1-α-β)Al_(α)Me_(β))(C_(γ)N_(1-γ))

A gas group A consisting of NH₃, N₂, and H₂ and a gas group B consisting of TiCl₄, Al(CH₃)₃, AlCl₃, MeCl_(n) (chloride of Me), N₂, and H₂ are supplied to a reactor of a chemical vapor deposition reaction apparatus which is to be used from separate gas supply tubes. The gas group A and the gas group B are supplied into the reaction apparatus such that the gas flows over time intervals with a specific cycle for a shorter time than the cycle and a phase difference in a shorter time than the gas supply time occurs in the gas supply of the gas group A and the gas group B, thereby temporarily changing the reaction gas composition on the surface of the tool body among the gas group A, mixed gas of the gas group A and the gas group B, and the gas group B. Incidentally, there is no need to introduce a gas discharge process over a long time intended to strictly substitute the gas in the present invention. Therefore, it is also possible to realize a gas supply method by rotating a gas supply port, rotating a tool body, or reciprocating the tool body to temporarily change the reaction gas composition on the surface of the tool body among mixed gas mainly containing the gas group A (first reaction gas), mixed gas of the gas group A and the gas group B (second reaction gas), and mixed gas mainly containing the gas group B (third reaction gas).

The (Ti_(1-α-β)Al_(α)Me_(β))(C_(γ)N_(1-γ)) layer with a predetermined target layer thickness is formed by performing a thermal CVD method on the surface of the tool body for a predetermined time by setting the reaction gas composition (% by volume with respect to the total of the gas group A and the gas group B) to NH₃: 1.0 to 1.5%, N₂: 1.0 to 2.0%, and H₂: 55 to 60% as the gas group A, AlCl₃: 0.6 to 0.9%, TiCl₄: 0.2 to 0.3%, MeCl_(n) (chloride of Me): 0.1 to 0.2%, Al(CH₃)₃: 0 to 0.5%, N₂: 12.5 to 15.0%, and H₂: the remaining amount as the gas group B, for example, under conditions of a reaction atmosphere pressure: 4.5 to 5.0 kPa, a reaction atmosphere temperature: 700 to 900° C., a supply cycle: 1 to 5 seconds, a gas supply time per cycle: 0.15 to 0.25 seconds, and a supply phase difference between the gas group A and the gas group B: 0.10 to 0.20 seconds.

Thus, local strain in crystal lattice is formed in the crystal grains due to introduction of local unevenness in composition, dislocation, and point defect, and it is possible to change degrees of {111} orientation of the crystal grains on the side of the surface of the tool body and on the side of the film surface, by supplying the gas group A and the gas group B such that a difference occurs between a time at which the gas group A reaches the surface of the tool body and a time at which the gas group B reaches the surface of the tool body, setting NH₃: 1.0 to 1.5% as a nitrogen raw material gas in the gas group A, and setting AlCl₃: 0.6 to 0.9%, TiCl₄: 0.2 to 0.3%, MeCl_(n) (chloride of Me): 0.1 to 0.2%, and Al(CH₃)₃: 0 to 0.5% as metal chloride raw materials or carbon raw materials in the gas group B as described above. The present inventors have found that as a result, toughness is significantly improved. The present inventors have found that as a result, the hard coating layer can exhibit an excellent cutting performance in use for a long period of time even in a case in which the coated tool is used in a high-speed intermittent cutting of alloy steel or the like in which an intermittent and impact load are exterted on the cutting edge.

(3) Concerning (Cr_(1-p)Al_(p))(C_(q)N_(1-q)) Layer

A gas group A consisting of NH₃, N₂, and H₂ and a gas group B consisting of CrCl₃, AlCl₃, Al(CH₃)₃, N₂, and H₂ are supplied to a reactor of a chemical vapor deposition reaction apparatus used from separate gas supply tubes. The gas group A and the gas group B are supplied into the reaction apparatus such that the gas flows over time intervals with a specific cycle for a shorter time than the cycle and a phase difference in a shorter time than the gas supply time occurs in the gas supply of the gas group A and the gas group B, thereby temporarily changing the reaction gas composition on the surface of the tool body among the gas group A, mixed gas of the gas group A and the gas group B, and the gas group B. Incidentally, there is no need to introduce a gas discharge process over a long time intended to strictly substitute the gas in the present invention. Therefore, it is also possible to realize a gas supply method by rotating a gas supply port, rotating a tool body, or reciprocating the tool body to temporarily change the reaction gas composition on the surface of the tool body among mixed gas mainly containing the gas group A (first reaction gas), mixed gas of the gas group A and the gas group B (second reaction gas), and mixed gas mainly containing the gas group B (third reaction gas).

The (Cr_(1-p)Al_(p))(C_(q)N_(1-q)) layer with a predetermined target layer thickness is formed by performing a thermal CVD method on the surface of the tool body for a predetermined time by setting the reaction gas composition (% by volume with respect to the total of the gas group A and the gas group B) to NH₃: 1.0 to 1.5%, N₂: 1.0 to 2.0%, and H₂: 55 to 60% as the gas group A, AlCl₃: 0.6 to 0.9%, CrCl₃: 0.2 to 0.3%, Al(CH₃)₃: 0 to 0.5%, N₂: 12.5 to 15.0%, and H₂: the remaining amount as the gas group B, for example, under conditions of a reaction atmosphere pressure: 4.5 to 5.0 kP, a reaction atmosphere temperature: 750 to 900° C., a supply cycle: 1 to 5 seconds, a gas supply time per cycle: 0.15 to 0.25 seconds, and a supply phase difference between the gas group A and the gas group B: 0.10 to 0.20 seconds.

Thus, local strain in crystal lattice is formed in the crystal grains due to introduction of local unevenness in composition, dislocation, and point defect, and it is possible to change degrees of {111} orientation of the crystal grains on the side of the surface of the tool body and on the side of the film surface, by supplying the gas group A and the gas group B such that a difference occurs between a time at which the gas group A reaches the surface of the tool body and a time at which the gas group B reaches the surface of the tool body, setting NH₃: 1.0 to 1.5% as a nitrogen raw material gas in the gas group A, and setting AlCl₃: 0.6 to 0.9%, CrCl₃: 0.2 to 0.3%, and Al(CH₃)₃: 0 to 0.5% as metal chloride raw materials or carbon raw materials in the gas group B as described above. The present inventors have found that as a result, toughness is significantly improved while wear resistance is maintained. The present inventors have found that as a result, fracture resistance and chipping resistance, in particular, are improved, and the hard coating layer can exhibit an excellent cutting performance in use for a long period of time even in a case in which the coated tool is used in a high-speed intermittent cutting of alloy steel or the like in which an intermittent and impact load are exterted on the cutting edge.

The present invention has been made on the basis of the aforementioned knowledge and has aspects described below.

(1) A surface-coated cutting tool in which a hard coating layer is formed on a surface of a tool body that is formed of any of tungsten-carbide-based cemented carbide, titanium-carbonitride-based cermet, and a cubic boron-nitride-based ultra-high-pressure sintered body, wherein

(a) the hard coating layer contains at least any of a layer of a complex nitride or a complex carbonitride of Ti and Al or a layer of a complex nitride or a complex carbonitride of Ti, Al, and Me (where Me is one kind of element selected from Si, Zr, B, V, and Cr), or a layer of a complex nitride or a complex carbonitride of Cr and Al, with an average layer thickness of 2 to 20 μm,

(b) the layer of a complex nitride or a complex carbonitride contains at least a phase of a complex nitride or a complex carbonitride that has an NaCl-type face-centered cubic structure,

(c) in a case in which crystal orientations of crystal grains that have NaCl-type face-centered cubic structures from among crystal grains that form the layer of a complex nitride or a complex carbonitride are analyzed in a vertical sectional direction by using an electron backscatter diffraction apparatus, and average crystal grain misorientations in the individual crystal grains are obtained, crystal grains with average crystal grain misorientations of 2 degrees or more are present at an area ratio of 20% with respect to the entire area of the layer of a complex nitride or a complex carbonitride,

(d) further, in a case in which inclined angles formed by normal lines of {111} planes, which are crystal plane, with respect to a normal line direction of a surface of a tool body of the crystal grains are measured in a region on a side of the tool body and a region on a side of the surface obtained by equally dividing the layer of a complex nitride or a complex carbonitride into two regions in a layer thickness direction, and frequencies at which measured inclined angles within a range of 0 to 45 degrees with respect to the normal line direction are present from among the measured inclined angles in the respective sections obtained by dividing the inclined angles into each pitch of 0.25 degrees are aggregated,

-   -   in a case where a ratio of total frequencies of the presence in         a range of 0 to 12 degrees with respect to the entire         frequencies in inclined angle frequency distribution is set as         be M_(deg), M_(deg) ranges from 10 to 40% in the region on the         side of the tool body, and     -   in a case where a highest peak is present in an inclined angle         section within a range of 0 to 12 degrees in a region on the         side of the surface, a ratio of total frequencies of the         presence in the range of 0 to 12 degrees with respect to the         entire frequencies in inclined angle frequency distribution is         set as be N_(deg), N_(deg) is M_(deg)+10 to M_(deg)+30%.

(2) The surface-coated cutting tool according to (1), in which the layer of a complex nitride or a complex carbonitride is a layer of a complex nitride or a complex carbonitride of Ti and Al, and in a case in which a composition thereof is represented by a composition formula: (Ti_(1-x)Al_(x))(C_(y)N_(1-y)), an average content ratio x_(avg) of Al with respect to the total amount of Ti and Al and an average content ratio y_(avg) of C with respect to the total amount of C and N (where both x_(avg) and y_(avg) are atomic ratios) in the layer of a complex nitride or a complex carbonitride satisfy 0.60≤x_(avg)≤0.95 and 0≤y_(avg)≤0.005, respectively.

(3) The surface-coated cutting tool according to (1), in which the layer of a complex nitride or a complex carbonitride is a layer of a complex nitride or a complex carbonitride of Ti, Al, and Me (where Me is one kind of element selected from Si, Zr, B, V, and Cr), and in a case in which a composition thereof is represented by a composition formula: (Ti_(1-α-β)Al_(α)Me_(β))(C_(γ)N_(1-γ)), an average content ratio α_(avg) of Al with respect to the total amount of Ti, Al, and Me, an average content ratio β_(avg) of Me with respect to the total amount of Ti, Al, and Me, and an average content ratio γ_(avg) of C with respect to the total amount of C and N (where all of α_(avg), β_(avg) and γ_(avg) are atomic ratios) in the layer of a complex nitride or a complex carbonitride satisfy 0.60≤α_(avg), 0.005≤β_(avg≤)0.10, 0≤γ_(avg)≤0.005, and 0.605≤α_(avg)+β_(avg)≤0.95, respectively.

(4) The surface-coated cutting tool according to (1), in which the layer of a complex nitride or a complex carbonitride is a layer of a complex nitride or a complex carbonitride of Cr and Al, and in a case in which a composition thereof is represented by a composition formula: (Cr_(1-p)Al_(p))(C_(q)N_(1-q)), an average content ratio p_(avg) of Al with respect to the total amount of Cr and Al and an average content ratio q_(avg) of C with respect to the total amount of C and N (where both p_(avg) and q_(avg) are atomic ratios) in the layer of a complex nitride or a complex carbonitride satisfy 0.70≤p_(avg)≤0.95 and 0≤q_(avg≤)0.005, respectively.

(5) The surface-coated cutting tool according to any one of (1) to (4), in which the layer of a complex nitride or a complex carbonitride contains at least 70% by area or more of a phase of a complex nitride or a complex carbonitride that has an NaCl-type face-centered cubic structure.

(6) The surface-coated cutting tool according to any one of (1) to (5), in which in a case where the layer of a complex nitride or a complex carbonitride is observed in a vertical sectional direction of the layer, the layer of a complex nitride or a complex carbonitride has a columnar structure in which an average crystal grain width W ranges from 0.1 to 2 μm and an average aspect ratio A ranges from 2 to 10 of the individual crystal grains that have NaCl-type face-centered cubic structures.

(7) The surface-coated cutting tool according to any one of (1) to (6), in which a lower layer that is formed of a Ti compound layer including one layer or two or more layers from among a carbide layer, a nitride layer, a carbonitride layer, a oxycarbide layer, and a oxycarbonitride layer of Ti and that has a total average layer thickness of 0.1 to 20 μm is present between the tool body and the layer of a complex nitride or a complex carbonitride.

(8) The surface-coated cutting tool according to any one of (1) to (7), in which an upper layer that contains at least an aluminum oxide layer and has a total average layer thickness of 1 to 25 μm is formed above the layer of a complex nitride or a complex carbonitride.

(9) A manufacturing method of the surface-coated cutting tool according to any one of (1) to (8), comprising: forming the layer of a complex nitride or a complex carbonitride by a chemical vapor deposition method in which at least trimethyl aluminum is contained as a reaction gas component.

Note that the “average crystal grain misorientation” means a value of grain orientation spread (GOS), which will be described later.

Effects of the Invention

By configuring a surface-coated cutting tool in which a hard coating layer is formed on a surface of a tool body according to an aspect of the present invention (hereinafter, referred to as “the surface-coated cutting tool according to the present invention” or “the cutting tool according to the present invention”) such that the hard coating layer contains at least any of a layer of a complex nitride or a complex carbonitride of Ti and Al or a layer of a complex nitride or a complex carbonitride of Ti, Al, and Me (where Me is one kind of element selected from Si, Zr, B, V, and Cr), or a layer of a complex nitride or a complex carbonitride of Cr and Al, with an average layer thickness of 2 to 20 μm, and in a case in which some crystal grains that form the layer of a complex nitride or a complex carbonitride have cubic structures, crystal orientations of crystal grains that have cubic structures from among crystal grains that form the layer of a complex nitride or a complex carbonitride are analyzed in a vertical sectional direction by using an electron backscatter diffraction apparatus, and average crystal grain misorientations in the individual crystal grains are obtained, crystal grains with average crystal grain misorientations of 2 degrees or more are present at an area ratio of 20% with respect to the entire area of the layer of a complex nitride or a complex carbonitride, further, in a case in which inclined angles formed by normal lines of {111} planes, which are crystal planes, with respect to a normal line direction of a surface of a tool body of the crystal grains are measured in a region on a side of the tool body and a region on a side of the surface obtained by equally dividing the layer of a complex nitride or a complex carbonitride into two regions in a layer thickness direction, and frequencies at which measured inclined angles within a range of 0 to 45 degrees with respect to the normal line direction are present from among the measured inclined angles in the respective sections obtained by dividing the inclined angles into each pitch of 0.25 degrees are aggregated, a) M_(deg) ranges from 10 to 40% when a ratio of total frequencies of the presence in a range of 0 to 12 degrees with respect to the entire frequencies in inclined angle frequency distribution is set as be M_(deg), and b) N_(deg) is M_(deg)+10 to M_(deg)+30% when a highest peak is present in an inclined angle section within a range of 0 to 12 degrees in a region on the side of the surface, and a ratio of total frequencies of the presence in the range of 0 to 12 degrees with respect to the entire frequencies in inclined angle frequency distribution is set as be N_(deg), and in a case in which the layer of a complex nitride or a complex carbonitride is observed from the side of the film section, the layer of a complex nitride or a complex carbonitride has a columnar structure in which an average crystal grain width W ranges from 0.1 to 2 μm and an average aspect ratio A ranges from 2 to 10 of the individual crystal grains that have NaCl-type face-centered cubic structures, strain occurs in the crystal grains that have cubic structures, and grain boundary slipping of the crystal grains is suppressed due to an increase in degrees of the {111) orientation. Therefore, the hardness and toughness of the crystal gains are improved. As a result, an effect that chipping resistance is improved without degrading wear resistance is achieved, the hard coating layer exhibits a superior cutting performance in use over a long period of time, and a long life of the coated tool is achieved, as compared with the hard coating layer in the related art.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an explanatory outline diagram showing a method of measuring an average crystal grain misorientation of a crystal grain that has an NaCl-type face-centered cubic structure (cubic crystal) in a layer of a complex nitride or a complex carbonitride of Ti and Al, Ti, Al and Me, or Cr and Al in a coated tool according to the present invention.

FIG. 2 is a film configuration diagram schematically showing a section of a layer of a complex nitride or a complex carbonitride of Ti and Al, Ti, Al and Me, or Cr and Al, which forms a hard coating layer in a surface-coated cutting tool according to the present invention.

FIG. 3 shows an example of histogram regarding an area ratio of average crystal grain misorientations (GOS values) of the individual crystal grains that have cubic structures in a section of the layer of the complex nitride or the complex carbonitride of Ti and Al, which forms a hard coating layer in the coated tool according to the present invention. The dotted line in the vertical direction in the histogram represents a boundary at which the average crystal grain misorientation is 2°, and the bars on the right side of the dotted line in the vertical direction in FIG. 3 represent those with an average crystal grain misorientation of equal to or greater than 2°.

FIG. 4 shows an example of histogram regarding an area ratio of average crystal grain misorientations (GOS values) of the individual crystal grains that have cubic structures in a section of a layer of a complex nitride or a layer of a complex carbonitride of Ti and Al that forms a hard coating layer in a coated tool according to a comparative example. The dotted line in the vertical direction in the histogram represents a boundary at which the average crystal grain misorientation is 2°, and the bars on the right side of the dotted line in the vertical direction in FIG. 4 represent those with the average crystal grain misorientation of equal to or greater than 2°.

FIG. 5 shows an example of an inclined angle frequency distribution graph of a created {111} plane in a region on a side of a tool body of a layer of a complex nitride or a complex carbonitride of Ti and Al, which forms a hard coating layer in the coated tool according to the present invention. An aggregation frequency is represented by a relative value standardized on the assumption that the maximum aggregation frequency is 100.

FIG. 6 shows an inclined angle frequency distribution graph of a created {111} plane in a region on a side of a surface of a layer of a complex nitride or a complex carbonitride of Ti and Al, which forms a hard coating layer in the coated tool according to the present invention. The aggregation frequency is represented by a relative value standardized on the assumption that the maximum aggregation frequency is 100.

FIG. 7 shows an example of histogram regarding an area ratio of average crystal grain misorientations (GOS values) of the individual crystal grains that have cubic structures in a section of a layer of a complex nitride or a layer of a complex carbonitride of Ti, Al, and Me, which forms a hard coating layer in the coated tool according to the present invention. The dotted line in the vertical direction in the histogram represents a boundary at which the average crystal grain misorientation is 2°, and the bars on the right side of the dotted line in the vertical direction in FIG. 7 represent those with the average crystal grain misorientation of equal to or greater than 2°.

FIG. 8 shows an example of histogram regarding an area ratio of average crystal grain misorientations (GOS values) of the individual crystal grains that have cubic structures in a section of a layer of a complex nitride or a layer of a complex carbonitride of Ti, Al and Me, which forms a hard coating layer in a coated tool according to a comparative example. The dotted line in the vertical direction in the histogram represents a boundary at which the average crystal grain misorientation is 2°, and the bars on the right side of the dotted line in the vertical direction in FIG. 8 represent those with the average crystal grain misorientation of equal to or greater than 2°.

FIG. 9 shows an example of an inclined angle frequency distribution graph of a created {111} plane in a region on a side of a tool body of a layer of a complex nitride or a complex carbonitride of Ti and Al, which forms a hard coating layer in the coated tool according to the present invention. The aggregation frequency is represented by a relative value standardized on the assumption that the maximum aggregation frequency is 100.

FIG. 10 shows an example of an inclined angle frequency distribution graph of a created {111} plane in a region on a side of a surface of a layer of a complex nitride or a complex carbonitride of Ti, Al, and Me, which forms a hard coating layer in the coated tool according to the present invention. The aggregation frequency is represented by a relative value standardized on the assumption that the maximum aggregation frequency is 100.

FIG. 11 shows an example of histogram regarding an area ratio of average crystal grain misorientations (GOS values) of the individual crystal grains that have cubic structures in a section of a layer of a complex nitride or a layer of a complex carbonitride of Cr and Al, which forms a hard coating layer in the coated tool according to the present invention. The dotted line in the vertical direction in the histogram represents a boundary at which the average crystal grain misorientation is 2°, and the bars on the right side of the dotted line in the vertical direction in FIG. 11 represent those with the average crystal grain misorientation of equal to or greater than 2°.

FIG. 12 shows an example of histogram regarding an area ratio of average crystal grain misorientations (GOS values) of the individual crystal grains that have cubic structures in a section of a layer of a complex nitride or a layer of a complex carbonitride of Cr and Al, which forms a hard coating layer in a coated tool according to a comparative example. The dotted line in the vertical direction in the histogram represents a boundary at which the average crystal grain misorientation is 2°, and the bars on the right side of the dotted line in the vertical direction in FIG. 12 represent those with the average crystal grain misorientation of equal to or greater than 2°.

FIG. 13 shows an example of an inclined angle frequency distribution graph of a created {111} plane in a region on a side of a tool body of a layer of a complex nitride or a complex carbonitride of Cr and Al, which forms a hard coating layer in the coated tool according to the present invention. The aggregation frequency is represented by a relative value standardized on the assumption that the maximum aggregation frequency is 100.

FIG. 14 shows an example of an inclined angle frequency distribution graph of a created {111} plane in a region on a side of a surface of a layer of a complex nitride or a complex carbonitride of Cr and Al, which forms a hard coating layer in the coated tool according to the present invention. The aggregation frequency is represented by a relative value standardized on the assumption that the maximum aggregation frequency is 100.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments to implement the present invention will be described below.

Average Layer Thickness of Layer of a Complex Nitride or a Complex Carbonitride that Forms Hard Coating Layer:

A hard coating layer that has a surface-coated cutting tool according to the present invention contains at least any of a layer of a complex nitride or a complex carbonitride of chemically-vapor-deposited Ti and Al (composition formula: (Ti_(1-x)Al_(x))(C_(y)N_(1-y))), a layer of a complex nitride or a complex carbonitride of Ti, Al, and Me (composition formula: (Ti_(1-α-β)Al_(α)Me_(β))(C_(γ)N_(1-γ))), or a layer of a complex nitride or a complex carbonitride of Cr and Al (composition formula: (Cr_(1-p)Al_(p))(C_(q)N_(1-q))). This layer of a complex nitride or a complex carbonitride has high hardness and excellent wear resistance, and effects are significantly exhibited especially when an average layer thickness ranges from 2 to 20 μm. This is because it is not possible to sufficiently secure wear resistance in use over a long period of time when the average layer thickness is less than 2 μm that is thin, and meanwhile, the crystal grains in the layer of a complex nitride or a complex carbonitride tend to become coarse and chipping tends to occur when the average layer thickness exceeds 20 μm. Therefore, the average layer thickness is defined as 2 to 20 μm.

Composition of layer of a complex nitride or a complex carbonitride that forms hard coating layer:

(1) Concerning Complex Nitride or Complex Carbonitride of Ti and Al According to the Present Invention

In a case in which the composition is represented by a composition formula: (Ti_(1-x)Al_(x))(C_(y)N_(1-y)), it is preferable that an average content ratio x_(avg) of Al with respect to the total amount of Ti and Al and an average content ratio y_(avg) of C with respect to the total amount of C and N (where both x_(avg) and y_(avg) are atomic ratios) satisfy 0.60≤x_(avg)≤0.95 and 0≤y_(avg)≤0.005, respectively.

This is because wear resistance is not sufficient in a case in which the coated tool is used in high-speed intermittent cutting of alloy steel or the like since the layer of a complex nitride or a complex carbonitride of Ti and Al has poor hardness when the average content ratio x_(avg) of Al is less than 0.60. Meanwhile, the average content ratio x_(avg) of Al exceeding 0.95 brings about a relative decrease in the content ratio of Ti, thus leads to embrittlement, and degrades chipping resistance. Therefore, the average content ratio x_(avg) of Al is defined as 0.60≤x_(avg≤)0.95.

In addition, when the content ratio (atomic ratio) y_(avg) of the C component included in the layer of a complex nitride or a complex carbonitride is low and within a range of 0≤y_(avg)≤0.005, adhesion between the layer of a complex nitride or a complex carbonitride and a tool body or a lower layer is increased, and lubricity is increased, thereby alleviating impacts at the time of cutting, and improving fracture resistance and chipping resistance of the layer of a complex nitride or a complex carbonitride as a result. Meanwhile, it is not preferable that the average content ratio y_(avg) of the C component deviate from the range of 0≤y_(avg)≤0.005 since toughness of the layer of a complex nitride or a complex carbonitride is then degraded, and fracture resistance and chipping resistance are thus degraded in an opposite manner Therefore, the average content ratio y_(avg) of the C component is defined as 0≤y_(avg)≤0.005.

(2) Concerning Complex Nitride or Complex Carbonitride of Ti, Al, and Me According to the Present Invention

In a case in which the composition is represented by a composition formula: (Ti_(1-α-β)Al_(α)Me_(β))(C_(γ)N_(1-γ)) (where Me is one kind of element selected from Si, Zr, B, V, and Cr), it is preferable to control average content ratios such that an average content ratio α_(avg) of Al with respect to the total amount of Ti, Al, and Me, an average content ratio β_(avg) of Me with respect to the total amount of Ti, Al, and Me, and an average content ratio γ_(avg) of C with respect to the total amount of C and N (where all of a α_(avg), β_(avg) and γ_(avg) are atomic ratios) satisfy 0.60≤α_(avg), 0.005≤β_(avg)≤0.10, 0≤γ_(avg)≤0.005, and 0.605≤α_(avg)+β_(avg)≤0.95.

This is because hardness of the layer of a complex nitride or a complex carbonitride of Ti, Al and Me is degraded when the average content ratio α_(avg) of Al is less than 0.60, and wear resistance is thus not sufficient in a case in which the coated tool is used in high-speed intermittent cutting of alloy steel or the like.

Since hardness of the layer of a complex nitride or a complex carbonitride of Ti, Al, and Me is degraded when the average content ratio β_(avg) of Me is less than 0.005, wear resistance is not sufficient in a case in which the coated tool is used in high-speed intermittent cutting of alloy steel or the like. Meanwhile, when the average content ratio β_(avg) of Me exceeds 0.10, toughness of the layer of a complex nitride or a complex carbonitride of Ti, Al, and Me is degraded due to segregation or the like of Me at the grain boundaries, and chipping resistance is not sufficient in a case in which the coated tool is used in high-speed intermittent cutting of alloy steel or the like. Therefore, the average content ratio β_(avg) of Me is defined as 0.005≤β_(avg)≤0.10.

Meanwhile, when the sum α_(avg)+β_(avg) of the average content ratio α_(avg) of Al and the average content ratio β_(avg) of Me is less than 0.605, hardness of the layer of a complex nitride or a complex carbonitride of Ti, Al and Me is degraded, and wear resistance is thus not sufficient in a case in which the coated tool is used in high-speed intermittent cutting of alloy steel or the like. When the sum α_(xvg)+β_(avg) exceeds 0.95, the content ratio of Ti relatively decreases, which leads to embrittlement and degradation of chipping resistance. Therefore, the sum α_(avg)+β_(avg) of the average content ratio α_(avg) of Al and the average content ratio β_(avg) of Me is defined as 0.605≤α_(avg)+β_(avg)≤0.95.

Here, one kind of element selected from Si, Zr, B, V, and Cr is used as a specific component for Me.

Since in a case in which an Si component or a B component is used as Me such that β_(avg) is equal to or greater than 0.005, hardness of the layer of a complex nitride or a complex carbonitride is improved, and wear resistance is thus improved, a Zr component has an effect of reinforcing the crystal grain boundaries, a V component improves toughness, thus further improving chipping resistance, and the Cr component improves oxidation resistance, a longer tool life can then be expected. However, since the average content ratios of the Al component and the Ti component relatively decrease when the average content ratio β_(avg) of any of these components exceeds 0.10, and wear resistance or chipping resistance exhibits decrease trends, the average content ratio β_(avg) that exceeds 0.10 has to be avoided.

In addition, when the average content ratio (atomic ratio) γ_(avg) of C contained in the layer of a complex nitride or a complex carbonitride is low and within a range of 0≤γ_(avg)≤0.005, adhesion between the layer of a complex nitride or a complex carbonitride and the tool body or the lower layer is improved, and lubricity is improved, impacts at the time of cutting are thus alleviated, and as a result, fracture resistance and chipping resistance of the layer of a complex nitride or a complex carbonitride are improved. In contrast, when the average content ratio γ_(avg) of C is outside the range of 0≤γ_(avg)≤0.005, toughness of the layer of a complex nitride or a complex carbonitride is degraded, and fracture resistance and chipping resistance are thus degraded in an opposite manner, which is unfavorable. Therefore, the average content ratio γ_(avg) of C is defined as 0≤γ_(avg)≤0.005.

(3) Concerning Complex Nitride or Complex Carbonitride of Cr and Al

In a case in which the composition is represented by a composition formula (Cr_(1-p)Al_(p))(C_(q)N_(1-q)), it is preferable to control average content ratios such that an average content ratio p_(avg) of Al with respect to the total amount of Cr and Al and an average content ratio q_(avg) of C with respect to the total amount of C and N (where both p_(avg) and q_(avg) are atomic ratios) satisfy 0.70≤p_(avg)≤0.95 and 0≤q_(avg)≤0.005.

This is because high-temperature hardness of the layer of a complex nitride or a complex carbonitride of Cr and Al is degraded, and oxidation resistance thereof is also degraded when the average content ratio p_(avg) of Al is less than 0.70, and wear resistance is thus not sufficient in a case in which the coated tool is used in high-speed intermittent cutting of alloy steel or the like. Meanwhile, the average content ratio p_(avg) of Al exceeding 0.95 relatively decreases the content ratio of Cr, thus leads to embrittlement, and degrades chipping resistance. Therefore, the average content ratio p_(avg) of Al is defined as 0.70≤p_(avg)≤0.95.

In addition, when the content ratio (atomic ratio) q_(avg) of the C component contained in the layer of a complex nitride or a complex carbonitride is low and within a range of 0≤q_(avg)≤0.005, adhesion between the layer of a complex nitride or a complex carbonitride and the tool body or the lower layer is improved, lubricity is improved, impacts at the time of cutting are thus alleviated, and as a result, fracture resistance and chipping resistance of the layer of a complex nitride or a complex carbonitride are improved. Meanwhile, when the average content ratio of the C component is outside the range of 0≤q_(avg)≤0.005, toughness of the layer of a complex nitride or a complex carbonitride is degraded, and fracture resistance and chipping resistance are thus degraded in an opposite manner, which is unfavorable. Therefore, the average content ratio q_(avg) of the C component is defined as 0≤q_(avg)≤0.005.

Average Crystal Grain Misorientations (GOS Values) of Individual Crystal Grains that Form Layer of a Complex Nitride or a Complex Carbonitride and have Cubic Structures:

First, an electron backscatter diffraction apparatus is used to analyze the coated tool at intervals of 0.1 μm in the vertical sectional direction, and in a case in which there is a misorientation of 5 degrees or greater between adjacent measurement points P (hereinafter, referred to as pixels) as shown in FIG. 1, the point is defined as a grain boundary B in the present invention. The vertical sectional direction means a direction perpendicular to a vertical section. The vertical section means a section of a tool perpendicular to the surface of the tool body. In addition, a region surrounded by a grain boundary B is defined as one crystal grain. However, a pixel P that has misorientations of 5 degrees or greater with respect to all adjacent pixels P and is present alone is not regarded as a crystal grain, and a crystal grain to which two or more pixels are coupled is handled as a crystal grain.

Further, a value obtained by calculating misorientations between a certain pixel P in a crystal grain and all the other pixels in the same crystal grain and averaging the misorientations is defined as a grain orientation spread (GOS) value. An outline diagram is shown in FIG. 1. The GOS value is described in the literature “Transactions of the Japan Society of Mechanical Engineers, Series A, Vol. 71, No. 712 (2005-12), Article No. 05-0367 1722 to 1728”, for example. Note that the “average crystal grain misorientation” in the present invention means this GOS value. In a case in which a GOS value is represented by an equation, the GOS value can be expressed by the following equation, where n represents the number of pixels in the same crystal grain, i and j represents numbers applied to different pixels in the crystal grain (here, 1≤i and j≤n), and α_(ij(i*j)) represents a crystal misorientation obtained from a crystal orientation at a pixel i and a crystal orientation at a pixel j.

$\begin{matrix} {{G\; O\; S} = \frac{\sum\limits_{i,{j = 1}}^{n}\alpha_{{ij}{({i*j})}}}{n\left( {n - 1} \right)}} & \left\lbrack {{Expression}.\mspace{14mu} 1} \right\rbrack \end{matrix}$

Note that it is possible to state in other words that the average crystal grain misorientation, namely the GOS value is a numerical value acquired by obtaining misorientations between pixels P in a crystal grain and all the other pixels in the same crystal grain and averaging the values thereof, and becomes a larger numerical value as a continuous change in orientations in the crystal grain becomes larger.

An electron backscatter diffraction apparatus was used

(1) to analyze a layer of a complex nitride or a complex carbonitride of Ti and Al or a layer of a complex nitride or a complex carbonitride of Cr and Al at intervals of 0.1 μm in the vertical sectional direction thereof and perform measurement in the vertical sectional direction within a measurement range in five fields of view with a width of 10 μm and a longitudinal length of the film thickness,

(2) to measure a polished surface as a surface as a surface within a measurement range of 25×25 μm at intervals of 0.1 μm in a direction perpendicular to the surface of a layer of a complex nitride or a complex carbonitride of Ti, Al and Me in five fields of view,

the total numbers of pixels that belonged to crystal grains that had cubic structures and formed the layer of a complex nitride or a complex carbonitride were thus obtained, the average crystal grain misorientations were divided at intervals of 1 degree, and the pixels P of the crystal grains with the average crystal grain misorientations within a range of these values were aggregated and divided according to the total numbers of pixels, thereby enabling creation of a histogram that represented an area ratio of the average crystal grain misorientations. As a result, it was found that the crystal orientations in crystal grains varied, and that the crystal grains with the average crystal grain misorientations of 2 degrees or greater were present at an area ratio of 20% or greater with respect to the entire layer of a complex nitride or a complex carbonitride of Al and Ti in the obtained histogram (see FIG. 3 of the measurement in accordance with (1) described above for one example).

Since the crystal grains that form the layer of a complex nitride or a complex carbonitride of Al and Ti, the complex nitride or the complex carbonitride of Ti, Al, and Me, or the complex nitride or the complex carbonitride of Al and Cr included in the surface coated cutting tool according to the present invention include greater variation of crystal orientations in the crystal grains, that is, the crystal grains include strain as compared with crystal grains in the related art that form a TiAlN layer or a CrAlN layer as described above, this contributes to improvement in hardness and toughness.

A preferable area ratio of the crystal grains with the average crystal grain misorientations of 2 degrees or greater with respect to the area of the layer of a complex nitride or a complex carbonitride ranges from 30 to 60%. A more preferable area ratio of the crystal grains with the average crystal grain misorientations of 2 degrees or greater with respect to the area of the layer of a complex nitride or a complex carbonitride ranges from 35 to 55%. In addition, a further preferable area ratio of the crystal grains with the average crystal grain misorientations of 2 degrees or greater with respect to the area of the layer of a complex nitride or a complex carbonitride ranges from 40 to 50% in a case of the complex nitride or the complex carbonitride of Al and Ti or a complex nitride or a complex carbonitride of Al and Cr.

Crystal orientation in a region on side of tool body and region on side of surface, which is obtained by equally dividing layer of a complex nitride or a complex carbonitride into two regions in the layer thickness direction

Since crystal grains that form the layer of a complex nitride or a complex carbonitride are orientated in a greater degree in a normal line direction of the surface of the tool body, that is, toward the {111} plane on the side of the surface than on the side of the surface (boundary surface) of the tool body, effects specific to the present invention that grain boundary slipping of the crystal grains is suppressed and that toughness is improved are exhibited.

However, when a ratio of an increase in the degree of {111} plane orientation on the side of the surface is less than 10% as compared with the side of the tool body, the ratio of the increase in the degree of {111} plane orientation is low, and the effect of improving toughness while maintaining wear resistance expected in the present invention is not sufficiently exhibited. Meanwhile, when the ratio exceeds 30%, epitaxial growth of the crystals is inhibited due to a rapid change in the orientation, and toughness is rather degraded. In addition, it has been found that the ratio of the increase in the degree of the {111} plane orientation becomes equal to or greater than 30% when the degree of the {111} plane orientation on the side of the tool body is less than 10%, and that the ratio of the increase in the degree of the {111} plane orientation on the surface becomes less than 10% when the degree of the {111} plane orientation on the side of the tool body exceeds 40%. Therefore, in a case in which inclined angles formed by the normal lines of the {111} planes, which are crystal planes of the crystal grains, with respect to the normal line direction of the surface of the tool body are measured in the region on the side of the tool body and the region on the side of the surface, which are obtained by equally dividing the layer of a complex nitride or a complex carbonitride into two regions in the layer thickness direction, and frequencies at which the measured inclined angles are present in each section obtained by dividing the measured inclined within a range of 0 to 45 degrees with respect to the normal line direction into each pitch of 0.25 degrees are aggregated, a) M_(deg) ranges from 10 to 40% when a ratio of the total of the frequencies at which the measured inclined angles are present within a range of 0 to 12 degrees with respect to the total frequencies in the inclined angle frequency distribution in the region on the side of the tool body is set as be M_(deg), and b) N_(deg) is defined to be M_(deg)+10 to M_(deg) to 30% when the highest peak is present in the inclined angle sections in the range of 0 to 12 degrees and a ratio of the total frequencies at which the measured inclined angles are present within the range of 0 to 12 degrees with respect to the total frequencies in the inclined angle frequency distribution in the region on the side of the surface is set as Ndeg.

Area Ratio of Layer of a Complex Nitride or a Complex Carbonitride:

The layer of a complex nitride or a complex carbonitride of Ti and Al, Ti, Al and Me, or Cr and Al exhibits excellent wear resistance by at least a phase of a complex nitride or a complex carbonitride that has an NaCl-type face-centered cubic structure being contained, and exhibits especially excellent wear resistance by the area ratio thereof exceeding 70%.

Average crystal grain width W and average aspect ratio A of individual crystal grains that have cubic structures in layer of a complex nitride or a complex carbonitride:

The aforementioned effects that toughness and wear resistance are improved can be further exhibited by employing such a configuration in which the individual crystal grains that have cubic structures in the layer of a complex nitride or a complex carbonitride of Ti and Al, Ti, Al and Me, or Cr and Al have columnar structures with an average crystal grain width W of 0.1 to 2 μm and an average aspect ratio A of 2 to 10.

That is, the average crystal grain width W is set to 0.1 to 2 μm because when the average crystal grain width W is less than 0.1 μm, a ratio of atoms that belong to TiAlCN crystal grain boundaries, TiAlMeCN crystal grain boundaries, or CrAlCN crystal grain boundaries with respect to atoms exposed to the surface of the coated layer relatively increases, reactivity with a work material to be cut thus increases, and as a result, wear resistance cannot sufficiently be exhibited, and when the average crystal grain width W exceeds 2 μm, the ratio of the atoms that belong to the TiAlCN crystal grain boundaries, the TiAlMeCN crystal grain boundaries, or the CrAlCN crystal grain boundaries with respect to the entire coated layer relatively decreases, toughness is thus degraded, and chipping resistance cannot sufficiently be exhibited. Therefore, it is preferable to set the average crystal grain width W to 0.1 to 2 μm.

In addition, in a case in which the average aspect ratio A is less than 2, sufficient columnar structures are not achieved, this leads to dropping out of equiaxial crystals with low aspect ratios, and as a result, wear resistance cannot sufficiently be exhibited. Meanwhile, when the average aspect ratio A exceeds 10, the strength of the crystal grains themselves cannot be maintained, and chipping resistance is rather degraded, which is unfavorable. Therefore, it is preferable to set the average aspect ratio A to 2 to 10.

Note that for the average aspect ratio A in the present invention, an aspect ratio a (=1/w) of each crystal grain is calculated by observing the hard coating layer on a side of a film section perpendicular to the surface of the tool body in vertical section observation of the hard coating layer within a range including the width of 100μ and the height of the entire hard coating layer by using a scanning electron microscope, and measuring the crystal grain width w in a direction parallel to the surface of the body and the crystal grain length L in a direction perpendicular to the surface of the body, and the average value of the aspect ratios a obtained for the individual crystal grains is calculated for the average aspect ratio A. In addition, an average value of the crystal grain widths w obtained for the individual crystal grains is calculated for the average crystal grain width W.

Lower Layer and Upper Layer:

In addition, the layer of a complex nitride or a complex carbonitride of Ti and Al, Ti, Al and Me, or Cr and Al that the surface-coated cutting tool according to the present invention has exhibits sufficient effects alone. However, in a case in which a lower layer that is made of a Ti compound layer including one layer or two or more layers from among a carbide layer, a nitride layer, a carbonitride layer, a oxycarbide layer, and a oxycarbonitride layer of Ti and has a total average layer thickness of 0.1 to 20 μm is provided and/or in a case in which an upper layer that includes an aluminum oxide layer that has an average layer thickness of 1 to 25 μm is provided, superior properties can be produced along with the effects that these layers exhibit. In a case in which a lower layer that is formed of a Ti compound layer including one layer or two or more layers from among a carbide layer, a nitride layer, a carbonitride layer, a oxycarbide layer, and a oxycarbonitride layer of Ti, and the total average layer thickness of the lower layer is less than 0.1 μm, the effects of the lower layer are not sufficiently exhibited. Meanwhile, when the total average layer thickness of the lower layer exceeds 20 μm, the crystal grains tend to be coarse, and chipping tends to occur. In addition, when the total average layer thickness of the upper layer that includes an aluminum oxide layer is less than 1 μm, the effects of the upper layer are not sufficiently exhibited. Meanwhile, when the total average layer thickness of the upper layer exceeds 25 μm, the crystal grain tends to be coarse, and chipping tends to occur.

Note that a diagram schematically showing a section of the layer of a complex nitride or a complex carbonitride of Ti and Al, Ti, Al and Me, or Cr and Al that forms the hard coating layer according to the present invention is shown in FIG. 2.

EXAMPLES

Next, the coated tool according to the present invention will be more specifically described in examples. Note that although a coated tool that contains WC-based cemented carbide or TiCN-based cermet in a tool body will be described in examples, the same is applied for a case in which a cubic boron-nitride-based ultra-high-pressure sintered body is used for a tool body.

Example 1

WC powder, TiC powder, TaC powder, NbC powder, Cr₃C₂ powder, and Co powder with average grain sizes of 1 to 3 μm were prepared as raw material powder, the raw material powder was mixed together in the mixing compositions shown in Table 1, wax was further added thereto, the mixture was mixed with acetone in a ball mill for 24 hours, was dried in a reduced pressure, and was press-molded into a green compact at a pressure of 98 MPa, the green compact is vacuum-sintered under conditions in which it was held in vacuum of 5 Pa at a predetermined temperature within a range of 1370 to 1470° C. for 1 hour, and after the sintering, tool bodies A to C made of WC-based cemented carbide with an insert shape of ISO standard SEEN1203AFSN were respectively manufactured.

In addition, TiCN (at a mass ratio TiC/TiN=50/50) powder, Mo₂C powder, ZrC powder, NbC powder, WC powder, Co powder, and Ni powder with average grain sizes of 0.5 to 2 μm were prepared as raw material powder, the powder was mixed together in the mixing compositions shown in Table 2, the mixture was wet-mixed by ball mill for 24 hours, was dried, and was press-molded into a green compact at a pressure of 98 MPa, the green compact was sintered under conditions in which it was held in a nitrogen atmosphere of 1.3 kPa at a temperature of 1500° C. for 1 hour, and after the sintering, a tool body D made of TiCN-based cermet with an insert shape of ISO standard SEEN1203AFSN was manufactured.

Next, a chemical vapor deposition apparatus was used on the surfaces of these tool bodies A to D.

(a) to manufacture coated tools 1 to 15 according to the present invention under the forming conditions A to J shown in Tables 4 and 5, that is, by using a gas group A consisting of NH₂, N₂, and H₂ and a gas group B consisting of TiCl₄, Al(CH₃)₃, AlCl₃, N₂, and H₂ and performing a thermal CVD method for a predetermined period of time using a gas supply method in which a reaction gas composition was set to satisfy NH₃: 1.0 to 1.5%, N₂: 1.0 to 2.0%, and H₂: 55 to 60% as the gas group A and AlCl₃: 0.6 to 0.9%, TiCl₄: 0.2 to 0.3%, Al(CH₃)₃: 0 to 0.5%, N₂: 12.5 to 15.0%, and H₂ as the gas group B under conditions of a reaction atmosphere pressure: 4.5 to 5.0 kPa, a reaction atmosphere temperature: 700 to 900° C., a supply cycle: 1 to 5 seconds, a gas supply time per cycle: 0.15 to 0.25 seconds, and a supply phase difference between the gas group A and the gas group B: 0.10 to 0.20 seconds to form hard coating layers of (Ti_(1-x)Al_(x))(C_(y)N_(1-y)) layers, in which crystal grains that had cubic structures with average crystal grain misorientations of 2 degrees or greater as shown in Table 7 were present at area ratios shown in Table 7, which had target layer thicknesses shown in Table 7.

Note that for coated tools 6 to 13 according to the present invention, lower layers shown in Table 6 and/or upper layers shown in Table 7 were formed under forming conditions shown in Table 3.

For the purpose of comparison, hard coating layers that contained at least layer of a complex nitride or a complex carbonitrides of Ti and Al were deposited on surfaces of tool bodies A to D under the conditions shown in Tables 4 and 5 with the target layer thicknesses (μm) shown in Table 8 in a manner similar to those of coated tools 1 to 15 according to the present invention. At this time, Comparative coated tools 1 to 13 were manufactured by forming the hard coating layers such that the reaction gas composition on the surface of the tool bodies did not change temporarily in a process of forming the (Ti_(1-x)Al_(x))(C_(y)N_(1-y)) layer.

Note that the lower layers shown in Table 6 and/or the upper layers shown in Table 8 were formed under the forming conditions shown in Table 3 for Comparative coated tools 6 to 13 in a manner similar to those of coated tools 6 to 13 according to the present invention.

For reference, Reference coated tools 14 and 15 shown in Table 8 were manufactured by depositing (Ti_(1-x)Al_(x))(C_(y)N_(1-y)) layers in reference examples with target layer thicknesses by arc ion plating using a physical vapor deposition apparatus in the related art on the surfaces of the tool body B and the tool body C.

Note that conditions of the arc ion plating used for the vapor deposition in the reference examples were as follows:

(a) Aforementioned tool bodies B and C were ultrasonically washed in acetone and were attached to a rotation table in an arc ion plating apparatus along an outer circumferential portion at a position away from the center axis by a predetermined distance in a radial direction in a dried state, and an Al—Ti alloy with a predetermined composition was deployed for a cathode electrode (evaporation source).

(b) First, the inside of the apparatus was evacuated and was heated to 500° C. with a heater while being maintained at a vacuum of 10⁻² Pa or lower, a DC bias voltage of −1000V was then applied to the tool bodies that rotated while revolving on the aforementioned rotation table, a current of 200 A was caused to flow between the cathode electrode made of the Al—Ti alloy and an anode electrode to cause arc discharge and generate Al ions and Ti ions in the apparatus, and thereafter, the surfaces of the tool bodies were treated by bombard cleaning.

(c) Then, nitrogen gas was introduced as reaction gas into the apparatus to obtain a reaction atmosphere at 4 Pa, a DC bias voltage at −50 V was applied to the tool bodies that rotated while revolving on the rotation table, and a current of 120 A was caused to flow between the cathode electrode (evaporation source) made of the Al—Ti alloy and the anode electrode to cause arc discharge.

In addition, a scanning electron microscope (magnification: 5000 times) was used to measure sections of the respective constituent layers of coated tools 1 to 15 according to the present invention, Comparative coated tools 1 to 13 and Reference coated tools 14 and 15 in directions perpendicular to the tool bodies, and layer thicknesses at five points in an observation field of view were measured and averaged to obtain average layer thicknesses. All the layers had average layer thicknesses that were substantially the same as the target layer thicknesses shown in Tables 6 to 8.

In addition, for the average content ratio x_(avg) of Al in the layer of a complex nitride or a complex carbonitride, the average content ratio x_(avg) of Al was obtained from averages of obtained analysis results of characteristic X-rays at ten points by irradiating polished surface as a surfaces of the samples with electron beams from the side of the surfaces of the samples by using an electron microanalyzer (electron-probe-micro-analyzer: EPMA). The average content ratio y_(avg) of C was obtained by secondary ion mass analysis (secondary-ion-mass-spectroscopy: SIMS). The ranges of 70 μm×70 μm from the side of the surfaces of the samples were irradiated with ion beams, and concentrations of the components discharged by a sputtering effect were measured in a depth direction. The average content ratio y_(avg) of C represents an average value in the depth direction of the layer of a complex nitride or a complex carbonitride of Ti and Al. However, the content ratio of C excludes the content ratio of inevitable C contained even when gas containing C is intentionally not used as a gas raw material. Specifically, the content ratio (atomic ratio) of the C component contained in the layer of a complex nitride or a complex carbonitride in a case in which the supply amount of Al(CH₃)₃ is assumed to be 0 was obtained as the content ratio of inevitable C, and a value obtained by subtracting the content ratio of inevitable C from a content ratio (atomic ratio) of the C component contained in the layer of a complex nitride or a complex carbonitride obtained in a case in which Al(CH₃)₃ was intentionally supplied was obtained as y_(avg).

Furthermore, crystal orientations of the individual crystal grains that formed the layer of a complex nitride or a complex carbonitride of Ti and Al and had cubic structures were analyzed in the vertical sectional direction by using an electron backscatter diffraction apparatus, and in a case in which there were misorientations of 5 degrees or greater between adjacent pixels, that parts were regarded as grain boundaries, a region surrounded by grain boundaries was regarded as one crystal grain, crystal grain misorientations were obtained between a certain pixel in a crystal grain and all the other pixels in the same crystal grain, and the crystal grain misorientations were mapped by dividing a range of 0 to 10 degrees into sections of each 1 degree, that is, a section of equal to or greater than 0 degrees and less than 1 degree, a section of equal to or greater than 1 degree and less than 2 degrees, a section of equal to or greater than 2 degrees and less than 3 degrees, a section of equal to or greater than 3 degrees and less than 4 degrees, and the like. The area ratio of the crystal grains with the average crystal grain misorientations of 2 degrees or greater with respect to the entire layer of a complex nitride or a complex carbonitride of Ti and Al was obtained from the mapping diagram. The results are shown in Tables 7 and 8.

FIG. 3 shows an example of histogram of the average crystal grain misorientations (that is, GOS values) measured in the coated tool 8 according to the present invention, and FIG. 4 shows an example of histogram of the average crystal grain misorientations measured in the comparative coated tool 12.

In addition, for inclined angle frequency distribution of the hard coating layer, a section of the hard coating layer formed of the layer of complex carbonitride of Ti and Al that had cubic structures was placed in a body tube of a field emission-type scanning electron microscope in a state in which the section was polished, the polished surface as a surface was analyzed in a region on the side of the surface (boundary surface) of the tool body and a region on the side of the surface, which were obtained by equally dividing the polished surface as a surface into two regions in the layer thickness direction, the individual crystal grains that had cubic crystal grain lattice that was present within the measurement ranges were irradiated with electron beams at an acceleration voltage of 10 kV at an incident angle of 70 degrees with an irradiation current of 1 nA, within the measurement ranges of the region on the side of the tool body and the region on the side of the surface in the direction perpendicular to the tool body, and for the width of 10 μm for five fields of view at intervals of 0.1 μm/step in the horizontal direction of the tool body, inclined angles of normal lines of {111} planes, which were crystal planes of the crystal grains, with respect to a normal line of the surface of the tool body (a direction perpendicular to the surface of the tool body in the polished section) were measured by using an electron backscatter diffraction image apparatus, measured inclined angles within a range of 0 to 45 degrees from among the measured inclined angles were divided into sections at a pitch of 0.25 degrees on the basis of the measurement results, and frequencies at which the measured inclined angles were present in the respective sections were aggregated, thereby a ratio of frequencies at which the measured inclined angles were present within a range of 0 to 12 degrees being obtained. The results are shown in Tables 7 and 8.

FIG. 5 shows an example of the inclined angle frequency distribution measured in the region on the side of the tool body of the hard coating layer that is formed of the layer of complex carbonitride of Ti and Al of the coated tool according to the present invention, and FIG. 6 shows an example of the inclined angle frequency distribution measured in the region on the side of the surface of the hard coating layer that is formed of the layer of complex carbonitride of Ti and Al of the coated tool according to the present invention.

Further, analysis was performed at intervals of 0.1 μm in the vertical sectional direction by using an electron backscatter diffraction apparatus, measurement within a measurement range with a width of 10 μm and a vertical length of the film thickness in the vertical sectional direction was performed in five fields of view, the total number of pixels that belonged to the crystal grains that formed the layer of a complex nitride or a complex carbonitride and had cubic structures was obtained, and the area ratio of the crystal grains that had the layer of a complex nitride or a complex carbonitride and had the cubic structures was obtained from a ratio with respect to the total number of measured pixels in the measurement performed on the hard coating layer in the aforementioned five fields of view.

TABLE 1 Mixing composition (% by mass) Type Co TiC TaC NbC Cr₃C₂ WC Tool A 8.5 1.5 — 3.0 0.4 Remainder body B 9.0 — 1.8 0.2 — Remainder C 7.5 — — — — Remainder

TABLE 2 Mixing composition (% by mass) Type Co Ni ZrC NbC Mo₂C WC TiCN Tool D 8 5 1 6 6 10 Remainder body

TABLE 3 Forming conditions (pressure of reaction atmosphere indicates Constituent layer of hard coating layer kPa and temperature indicates ° C.)Forming conditions Formation Reaction atmosphere Type symbol Reaction gas composition (% by volume) Pressure Temperature (Ti_(1−X)Al_(x))(C_(Y)N_(1−Y)) TiAlCN TiAlCN See Table 4 See Table 5 See Table 5 layer Ti component TiC TiC TiCl₄: 4.2%, CH₄: 8.5%, H₂: remainder 7 900 layer TiN TiN-1 TiCl₄: 4.2%, N₂: 30%, H₂: remainder 30 850 TiN-2 TiCl₄: 4.2%, N_(g): 35%, H₂: remainder 50 900 1-TiCN 1-TiCN TiCl₄: 2%, CH₃CN: 0.7%, N₂: 10%, H₂: remainder 7 900 TiCN TiCN TiCl₄: 2%, CH₄: 1%, N₂: 15%, H₂: remainder 13 900 TiCO TiCO TiCl₄: 4.2%, CO: 4%, H₂: remainder 7 900 TiCNO TiCNO TiCl₄: 2%, CO: 1%, CH₄: 1%, N₂: 5%, H₂: remainder 13 900 Al₂O₃ layer Al₂O₃ Al₂O₃ AlCl₃: 2.2%, CO₂: 5.5%, HCl: 2.2%, H₂S: 0.2%, H₂: remainder 7 900

TABLE 4 Forming conditions Formation of hard (Reaction gas composition is represented by ratios with respect to a total for the gas group A and the gas group B.) coating layer Reaction gas group A Process type Formation symbol composition (% by volume) Reaction gas group B composition (% by volume) Film A NH₃: 1.5% N₂: 2.0% H₂: 55% AlCl₃: 0.6% TiCl₄: 0.2% N₂: 12.5% Al(CH₃)₃: 0% H₂: remainder forming B NH₃: 1.5% N₂: 1.0% H₂: 55% AlCl₃: 0.7% TiCl₄: 0.2% N₂: 13% Al(CH₃)₃: 0% H₂: remainder process C NH₃: 1.0% N₂: 1.0% H₂: 60% AlCl₃: 0.8% TiCl₄: 0.3% N₂: 14% Al(CH₃)₃: 0% H₂: remainder according to D NH₃: 1.0% N₂: 2.0% H₂: 60% AlCl₃: 0.6% TiCl₄: 0.2% N₂: 13.5% Al(CH₃)₃: 0% H₂: remainder the present E NH₃: 1.0% N₂: 1.0% H₂: 60% AlCl₃: 0.8% TiCl₄: 0.3% N₂: 13% Al(CH₃)₃: 0% H₂: remainder invention F NH₃: 1.0% N₂: 1.0% H₂: 55% AlCl₃: 0.6% TiCl₄: 0.3% N₂: 13.5% Al(CH₃)₃: 0.4% H₂: remainder G NH₃: 1.5% N₂: 1.0% H₂: 55% AlCl₃: 0.7% TiCl₄: 0.3% N₂: 14.5% Al(CH₃)₃: 0.2% H₂: remainder H NH₃: 1.5% N₂: 2.0% H₂: 60% AlCl₃: 0.7% TiCl₄: 0.3% N₂: 15% Al(CH₃)₃: 0% H₂: remainder I NH₃: 1.0% N₂: 1.0% H₂: 55% AlCl₃: 0.9% TiCl₄: 0.3% N₂: 14% Al(CH₃)₃: 0.5% H₂: remainder J NH₃: 1.5% N₂: 2.0% H₂: 60% AlCl₃: 0.9% TiCl₄: 0.2% N₂: 12.8% Al(CH₃)₃: 0% H₂: remainder Comparative A′ NH₃: 1.5% N₂: 2.0% H₂: 55% AlCl₃: 0.6% TiCl₄: 0.2% N₂: 12.5% Al(CH₃)₃: 0% H₂: remainder film forming B′ NH₃: 1.5% N₂: 1.0% H₂: 55% AlCl₃: 0.7% TiCl₄: 0.2% N₂: 13% Al(CH₃)₃: 0% H₂: remainder process C′ NH₃: 1.0% N₂: 1.0% H₂: 60% AlCl₃: 0.8% TiCl₄: 0.3% N₂: 14% Al(CH₃)₃: 0% H₂: remainder D′ NH₃: 1.0% N₂: 1.0% H₂: 60% AlCl₃: 0.8% TiCl₄: 0.2% N₂: 13.5% Al(CH₃)₃: 0% H₂: remainder E′ NH₃: 1.0% N₂: 1.0% H₂: 60% AlCl₃: 0.8% TiCl₄: 0.3% N₂: 13% Al(CH₃)₃: 0% H₂: remainder F′ NH₃: 1.0% N₂: 1.0% H₂: 55% AlCl₃: 0.6% TiCl₄: 0.3% N₂: 13.5% Al(CH₃)₃: 0.4% H₂: remainder G′ NH₃: 1.5% N₂: 1.0% H₂: 55% AlCl₃: 0.7% TiCl₄: 0.3% N₂: 14.5% Al(CH₃)₃: 0.2% H₂: remainder H′ NH₃: 1.5% N₂: 2.0% H₂: 60% AlCl₃: 0.7% TiCl₄: 0.3% N₂: 15% Al(CH₃)₃: 0% H₂: remainder I′ NH₃: 1.0% N₂: 1.0% H₂: 55% AlCl₃: 0.9% TiCl₄: 0.3% N₂: 14% Al(CH₃)₃: 0.5% H₂: remainder J′ NH₃: 1.5% N₂: 2.0% H₂: 60% AlCl₃: 0.9% TiCl₄: 0.2% N₂: 12.8% Al(CH₃)₃: 0% H₂: remainder

TABLE 5 Forming conditions (pressure of reaction atmosphere indicates kPa and temperature indicates ° C.) Forming conditions Phase difference in supply Gas group A Gas group B between Formation of hard Supply Supply gas group coating layer Supply time per Supply time per A and gas Formation cycle cycle cycle cycle group B Reaction atmosphere Process type symbol (seconds) (seconds) (seconds) (seconds) (seconds) Pressure Temperature Film A 5 0.2 5 0.2 0.15 4.7 800 forming B 1 0.2 1 0.2 0.15 4.7 800 process C 2.5 0.2 2.5 0.2 0.1 4.7 750 according to D 1.5 0.15 1.5 0.15 0.1 4.7 700 the present E 4 0.2 4 0.2 0.1 5 850 invention F 4.5 0.2 4.5 0.2 0.1 4.7 800 G 2.5 0.2 2.5 0.2 0.15 4.5 800 H 3 0.15 3 0.15 0.1 4.5 800 I 2 0.25 2 0.25 0.15 5 700 J 1.2 0.25 1.2 0.25 0.2 4.7 900 Comparative A′ — — — — — 4.7 800 film forming B′ — — — — — 4.7 800 process C′ — — — — — 4.7 750 D′ — — — — — 4.7 700 E′ — — — — — 5 850 F′ — — — — — 4.7 800 G′ — — — — — 4.5 800 H′ — — — — — 4.5 800 I′ — — — — — 5 700 J′ — — — — — 4.7 900

TABLE 6 Hard coating layer (Numerical values in the lower sections represent target average layer thickness (μm) of the layer.) Lower layer Tool body First Second Third Type symbol layer layer layer Coated tools 1 A — — — of the 2 B — — — present 3 C — — — invention/ 4 D — — — Comparative 5 A — — — coated 6 B TiC — — tools/ (0.5) Reference 7 C TiN-1 — — coated tools (0.3) 8 D TiN-1 1-TiCN — (0.5) (4) 9 A TiN-1 1-TiCN TiCN (0.3) (2) (0.7) 10 B — — — 11 C TiN-1 — — (0.5) 12 D TiC — — (1)   13 A TiN-1 — — (0.1) 14 B — — — 15 C — — —

TABLE 7 Hard coating layer TiAl complex carbide, carbonitride layer (Ti_(1−x)Al_(x))(C_(y)N_(1−y)) Area ratio of Formation crystal grains symbol of having process of average forming crystal grain Average TiAlCN misorientation crystal grain Average film (See Content equal to or Area ratio width w of aspect ratio Tool body Tables 4 ratio x_(avg) of Content ratio greater than 2 of cubic crystal A of crystal Type symbol and 5) Al of y_(avg) of C degrees (%) crystal (%) grains (μm) grains Coated tools 1 A A 0.78 0.0001 or less 51 100 0.7 2.0 according to 2 B B 0.93 0.0001 or less 46 100 0.8 5.0 the present 3 C C 0.75 0.0001 or less 41 94 0.8 2.2 invention 4 D D 0.73 0.0001 or less 30 100 0.4 10.0 5 A E 0.67 0.0001 or less 41 100 1.1 1.5 6 B F 0.89 0.0038 20 100 0.2 3.2 7 C G 0.81 0.0041 63 100 0.3 2.3 8 D H 0.80 0.0001 or less 54 100 0.1 2.3 9 A I 0.95 0.0022 37 65 0.1 3.1 10 B J 0.93 0.0001 or less 35 70 0.60 2.6 11 C A 0.74 0.0001 or less 53 98 1.1 3.5 12 D B 0.92 0.0001 or less 47 100 0.9 4.7 13 A C 0.72 0.0001 or less 36 93 0.7 1.8 14 B D 0.71 0.0001 or less 30 98 0.4 9.5 15 C E 0.68 0.0001 or less 42 100 0.8 1.4 Hard coating layer TiAl complex carbide, carbonitride layer (Ti_(1−x)Al_(x))(C_(y)N_(1−y)) Distribution Distribution ratio of ratio of frequencies frequencies at which at which inclined inclined angles of angles of normal lines normal lines Inclined of {111} of {111} angle planes are planes are section in present in a present in a which the range of 0 range of 0 highest peak to 12 to 12 is observed degrees in degrees in in the region Upper layer the region the region on the side (Numerical values in the lower on the side on the side of the Target layer sections represent target average layer of the tool of the surface thickness thickness (μm) of the layers. Type body M_(deg) surface N_(deg) (degrees) (μm) First layer Second layer Coated tools 1 29 59 4.75 to 5.00 4 — — according to 2 15 30 5.25 to 5.50 5 — — the present 3 16 39 11.75 to 12.00 3.5 — — invention 4 10 38 8.00 to 8.25 7 — — 5 32 51 2.75 to 3.00 6 — — 6 21 40 4.00 to 4.25 2 — — 7 27 45 4.50 to 4.75 6 — — 8 40 70 3.75 to 4.00 4 — — 9 35 61 2.00 to 2.25 8 — — 10 26 48 3.00 to 3.25 4.5 Al₂O₃ — (2.5) 11 28 58 4.25 to 4.50 5 TiCN Al₂O₃ (0.5) (3) 12 17 35 4.25 to 4.50 6 TiCO Al₂O₃ (1)   (2) 13 12 38 9.00 to 9.25 2.5 TiCNO Al₂O₃ (0.3) (1) 14 14 42 7.25 to 7.50 5 — — 15 34 56 4.50 to 4.75 3 — —

TABLE 8 Hard coating layer TiAl complex carbide, carbonitride layer (Ti_(1−x)Al_(x))(C_(y)N_(1−y)) Formation Average symbol of Area ratio of crystal crystal process of grains having average grain Average forming crystal grain width w of aspect Tool TiAlCN (See misorientation equal to Area ratio of crystal ratio A of body Tables 4 and Content ratio Content ratio or greater than 2 cubic crystal grains crystal Type symbol 5) x_(avg) of Al of y_(avg) of C degrees (%) (%) (μm) grains Comparative 1 A A′ 0.67 0.0001 or less 5 93 0.6 1.5 Coated tool 2 B B′ 0.91 0.0001 or less 7 100 0.7 4.5 3 C C′ 0.72 0.0001 or less 6 94 0.5 1.5 4 D D′ 0.69 0.0001 or less 12 100 0.4 2.1 5 A E′ 0.66 0.0001 or less 4 100 0.9 2.5 6 B F′ 0.84 0.0023 8 96 0.2 3.1 7 C G′ 0.78 0.0033 4 100 1.0 1.8 8 D H′ 0.62 0.0001 or less 5 100 0.4 0.8 9 A I′ 0.92 0.0041 6 71 0.2 1.2 10 B J′ 0.94 0.0001 or less 5 73 0.40 1.5 11 C A′ 0.69 0.0001 or less 4 95 0.8 3.2 12 D B′ 0.90 0.0001 or less 8 100 0.8 4.2 13 A C′ 0.69 0.0001 or less 4 95 0.8 1.3 Reference 14 B AIP 0.50 0.0001 or less 15 100 1.5 3.3 coated tool 15 C AIP 0.59 0.0001 or less 14 100 0.6 2.2 Hard coating layer TiAl complex carbide, carbonitride layer (Ti_(1−x)Al_(x))(C_(y)N_(1−y)) Distribution Distribution ratio of ratio of frequencies at frequencies at which inclined which inclined angles of angles of Inclined angle normal lines of normal lines of section in Upper layer {111} planes {111} planes which the (Numerical values in the are present in a are present in a highest peak lower sections represent range of 0 to 12 range of 0 to 12 is observed in target average layer degrees in the degrees in the the region on thickness (μm) of the region on the region on the the side of the Target layer layers. side of the tool side of the surface thickness First Second Type body M_(deg) surface N_(deg) (degrees) (μm) layer layer Comparative 1 33 37 14.25 to 14.50 4 — — Coated tool 2 25 31 32.00 to 32.25 5 — — 3 19 23 28.25 to 28.50 3.5 — — 4 24 19 26.75 to 27.00 7 — — 5 34 43 14.50 to 14.75 6 — — 6 27 22 32.75 to 33.00 2 — — 7 21 24 24.25 to 24.50 6 — — 8 24 28 23.25 to 24.50 4 — — 9 34 28 16.25 to 16.50 8 — — 10 22 17 41.50 to 41.75 4.5 Al₂O₃ — (2.5) 11 31 41 31.25 to 31.50 5 TiCN Al₂O₃ (0.5) (3) 12 26 32 31.25 to 31.50 6 TiCO Al₂O₃ (1)   (2) 13 21 23 32.25 to 32.50 2.5 TiCNO Al₂O₃ (0.3) (1) Reference 14 25 31 31.25 to 31.50 5 — — coated tool 15 19 24 32.25 to 32.50 3 — — (Note) “AIP” indicates a film formed through arc ion plating.

Next, all the aforementioned variety of coated tools, namely coated tools 1 to 15 according to the present invention, Comparative coated tools 1 to 13, and Reference coated tools 14 and 15 were subjected to the following dry high-speed intermittent cutting test and a center cutting machining test, which are types of high-speed intermittent cutting of alloy steel, in a state in which the coated tools were clamped with fixing jigs at tip ends of cutters made of tool steel with a cutter diameter of 125 mm, and wear width of a flank faces at all the cutting edges were measured. The results are shown in Table 9.

Tool body: tungsten-carbide-based cemented carbide, titanium-carbonitride-based cermet Cutting test: dry high-speed face milling, center cutting machining Work material: block material of JIS-SCM440 with a width of 100 mm and a length of 400 mm

Rotation speed: 892 min⁻¹

Cutting speed: 350 m/min

Depth of cut: 2.5 mm

Feed rate per tooth: 0.25 mm/tooth

Cutting time: 8 minutes

TABLE 9 Wear width Results of of a flank cutting test Type face (mm) Type (minutes) Coated tools 1 0.07 Comparative 1 2.2* according to 2 0.08 coated 2 3.5* the present 3 0.09 tools 3 2.1* invention 4 0.11 4 4.0* 5 0.12 5 4.6* 6 0.09 6 3.9* 7 0.07 7 3.4* 8 0.10 8 2.3* 9 0.14 9 1.8* 10 0.10 10 1.9* 11 0.09 11 4.6* 12 0.08 12 4.2* 13 0.13 13 2.3* 14 0.11 Reference 14 4.4* 15 0.12 coated tools 15 4.2* The * marks in the sections of the comparative coated tools and the reference coated tools denote cutting times (minutes) at which the life end was reached due to the occurrence of chipping.

Example 2

WC powder, TiC powder, TaC powder, NbC powder, Cr₃C₂ powder, TiN powder, and Co powder with average grain sizes of 1 to 3 μm were prepared as raw material powder, the raw material powder was mixed together in the mixing compositions shown in Table 10, wax was further added thereto, the mixture was mixed with acetone in a ball mill for 24 hours, was dried in a reduced pressure, and was press-molded into a green compact with a predetermined shape under a pressure of 98 MPa, the green compact is vacuum-sintered under conditions in which it was held in vacuum of 5 Pa at a predetermined temperature within a range of 1370 to 1470° C. for 1 hour, and after the sintering, tool bodies α to γ made of WC-based cemented carbide with an insert shape of ISO standard CNMG120412 were respectively manufactured by performing honing machining at R: 0.07 mm on cutting edge portions.

TiCN (mass ratio TiC/TiN=50/50) powder, NbC powder, WC powder, Co powder, and Ni powder with average grain sizes of 0.5 to 2 μm were prepared as raw material powder, the raw material powder was mixed together in the mixing compositions shown in Table 11, the mixture was wet mixed in a ball mill for 24 hours, was dried, and was press-molded into a green compact under a pressure of 98 MPa, the green compact is sintered under conditions in which it was held in nitrogen atmosphere at 1.3 kPa at a temperature of 1500° C. for 1 hour, and after the sintering, a tool body δ made of TiCN-based cermet with an insert shape of ISO standard CNMG120412 was manufactured by performing honing machining at R: 0.09 mm on a cutting edge portion.

Next, coated tools 16 to 30 according to the present invention shown in Table 13 were manufactured by using a chemical vapor deposition apparatus on the surfaces of these tool bodies α to γ and the tool body δ to deposit hard coating layers with target layer thicknesses, which included at least (Ti_(1-x)Al_(x))(C_(y)N_(1-y)), under the conditions shown in Tables 4 and 5 by a method similar to that in Example 1.

Note that the lower layers shown in Table 12 and/or the upper layers shown in Table 13 were formed for coated tools 19 to 28 according to the present invention under the forming conditions shown in Table 3.

In addition, for the purpose of comparison, Comparative coated tools 16 to 28 shown in Table 14 were manufactured by using a chemical vapor deposition apparatus on the surfaces of these tool bodies α to γ and the tool body δ to deposit hard coating layers with target layer thicknesses shown in Table 14 under the conditions shown in Tables 4 and 5 by a method similar to that for the coated tools according to the present invention.

Note that the lower layers shown in Table 12 and/or the upper layers shown in Table 14 were formed for Comparative coated tools 19 to 28 under the forming conditions shown in Table 3 in a manner similar to that for coated tools 19 to 28 according to the present invention.

For reference, Reference coated tools 29 and 30 shown in Table 14 were manufactured by depositing (Ti_(1-x)Al_(x))(C_(y)N_(1-y)) layers in the reference examples with target layer thicknesses on the surfaces of the tool body β and the tool body γ by arc ion plating using a physical vapor deposition apparatus in the related art.

Note that conditions similar to the conditions shown in Example 1 were used as conditions for the arc ion plating.

In addition, a scanning electron microscope (magnification: 5000 times) was used to measure sections of the respective constituent layers of coated tools 16 to 30 according to the present invention, Comparative coated tools 16 to 28, and Reference coated tools 29 and 30, and layer thicknesses at five points in an observation field of view were measured and averaged to obtain average layer thicknesses. All the layers had average layer thicknesses that were substantially the same as the target layer thicknesses shown in Tables 12 to 14.

Furthermore, crystal orientations of the individual crystal grains that formed the layer of a complex nitride or a complex carbonitride of Ti and Al and had cubic structures were analyzed in the vertical sectional direction by using an electron backscatter diffraction apparatus, and crystal grain misorientations were mapped by dividing a range of 0 to 10 degrees into sections of each 1 degree, that is, a section of equal to or greater than 0 degrees and less than 1 degree, a section of equal to or greater than 1 degree and less than 2 degrees, a section of equal to or greater than 2 degrees and less than 3 degrees, a section of equal to or greater than 3 degrees and less than 4 degrees, and the like. Average crystal grain misorientations and an area ratio of the crystal grains with the average crystal grain misorientations of 2 degrees or greater with respect to the entire layer of a complex nitride or a complex carbonitride of Ti and Al were obtained from the mapping diagram. The results are shown in Tables 13 and 14.

In addition, for inclined angle frequency distribution of the hard coating layer, a section of the hard coating layer formed of the layer of complex carbonitride of Ti and Al that had cubic structures was placed in a body tube of a field emission-type scanning electron microscope in a state in which the section was polished, the polished surface as a surface was analyzed in a region on the side of the surface (boundary surface) of the tool body and a region on the side of the surface, which were obtained by equally dividing the polished surface as a surface into two regions in the layer thickness direction, the individual crystal grains that had cubic crystal grain lattice that was present within measurement ranges in the region on the side of the tool body and in the region on the side of the surface were irradiated with electron beams at an acceleration voltage of 10 kV at an incident angle of 70 degrees with an irradiation current of 1 nA, inclined angles of normal lines of {111} planes, which were crystal planes of the crystal grains, with respect to a normal line of the surface of the tool body (a direction perpendicular to the surface of the tool body in the polished section) were measured for the width of 10 μm for five fields of view at intervals of 0.1 μm/step in the horizontal direction of the tool body by using an electron backscatter diffraction image apparatus, measured inclined angles within a range of 0 to 45 degrees from among the measured inclined angles were divided into sections at a pitch of 0.25 degrees on the basis of the measurement results, and frequencies at which the measured inclined angles were present in the respective sections were aggregated, thereby a ratio of frequencies at which the measured inclined angles were present within a range of 0 to 12 degrees being obtained. The results are shown in Tables 13 and 14.

TABLE 10 Mixing composition (% by mass) Type Co TiC ZrC TaC NbC Cr₃C₂ TiN WC Tool α 7.0 — 1.5 — 2.9 0.1 1.5 Remainder body β 8.1 2.6 — 4.0 0.5 1.1 Remainder γ 6.5 — — — — — — Remainder

TABLE 11 Mixing composition (% by mass) Type Co Ni NbC WC TiCN Tool body δ 11 4 6 15 Remainder

TABLE 12 Hard coating layer (The numerical values in the lower sections represent target average layer thicknesses (μm) of the layers.) Tool Lower layer body First Second Third Fourth Type symbol layer layer layer layer Coated tools 16 α — — — — according to the 17 β — — — — present invention/ 18 γ — — — — Comparative coated 19 δ TiC — — — tools/Reference (0.5) coated tools 20 α TiN-1 — — — (0.1) 21 β TiN-1 1-TiCN — — (0.5) (7) 22 γ TiN-1 1-TiCN TiN-2 — (0.3) (10)  (0.7) 23 δ TiN-1 1-TiCN TiCN TiN-2 (0.3) (4) (0.4) (0.3) 24 α — — — — 25 β TiN-1 — — (0.5) 26 γ TiC — — (1)   27 δ TiN-1 — — (0.1) 28 α TiN-1 — — (0.1) 29 β — — — 30 γ — — —

TABLE 13 Hard coating layer TiAl complex carbide, carbonitride layer (Ti_(1−x)Al_(x))(C_(y)N_(1−y)) Formation Average symbol of Area ratio of crystal crystal process of grains having average grain Average forming crystal grain width W aspect Tool TiAlCN (See Content Content misorientation equal Area ratio of of crystal ratio A of body Tables 4 and ratio x_(avg) ratio of y_(avg) to or greater than 2 cubic crystal grains crystal Type symbol 5) of Al of C degrees (%) (%) (μm) grains Coated 16 α A 0.71 0.0001 or 56 90 1.3 5.0 tools less according 17 β B 0.94 0.0001 or 45 100 0.4 3.0 to the less present 18 γ C 0.69 0.0001 or 39 93 0.9 3.2 invention less 19 δ D 0.78 0.0001 or 48 98 0.5 2.2 less 20 α E 0.69 0.0001 or 45 100 0.8 4.5 less 21 β F 0.83 0.0038 55 95 0.7 2.1 22 γ G 0.76 0.0023 33 100 2.0 3.1 23 δ H 0.63 0.0001 or 32 100 1.1 2.0 less 24 α I 0.93 0.0031 22 63 0.4 5.1 25 β J 0.92 0.0001 or 39 68 0.8 2.2 less 26 γ A 0.72 0.0001 or 58 93 0.8 7.0 less 27 δ B 0.93 0.0001 or 43 100 0.2 2.5 less 28 α C 0.69 0.0001 or 39 92 1.1 3.5 less 29 β D 0.81 0.0001 or 48 100 0.6 2.5 less 30 γ E 0.68 0.0001 or 51 100 0.6 2.0 less Hard coating layer TiAl complex carbide, carbonitride layer (Ti_(1−x)Al_(x))(C_(y)N_(1−y)) Distribution Distribution ratio of ratio of frequencies at frequencies at which inclined which inclined angles of angles of Inclined normal lines normal lines angle section of {111} of {111} in which the planes are planes are highest peak present in a present in a is observed Upper layer (Numerical values range of 0 to range of 0 to in the region in the lower sections 12 degrees in 12 degrees in on the side Target represent target average layer the region on the region on of the layer thickness (μm) of the layer.) the side of the the side of the surface thickness First Second Third Fourth Type tool body M_(deg) surface N_(deg) (degrees) (μm) layer layer layer layer Coated 16 15 30 5.25 to 5.50 12 — — — — tools according 17 21 40 3.00 to 3.25 6 — — — — to the present 18 24 44 2.50 to 2.75 7 — — — — invention 19 34 53 4.25 to 4.50 20 — — — — 20 1 41 3.50 to 3.75 16 — — — — 21 29 56 2.75 to 3.00 3 — — — — 22 17 29 4.50 to 4.75 8 TiN-2 — — — (0.7) 23 35 59 4.75 to 5.00 4 TiCN TiN-2 — — (0.4) (0.3) 24 37 52 6.00 to 6.55 7 Al₂O₃ — — — (2)   25 16 39 10.00 to 10.25 15 TiCN Al₂O₃ — — (0.5) (2.5) 26 15 30 4.75 to 5.00 16 TiCO Al₂O₃ — — (1)   (2)   27 21 42 3.25 to 3.50 4 TiCNO Al₂O₃ — — (0.3) (1)   28 25 47 3.50 to 3.75 9 TiN-2 TiCN TiCNO Al₂O₃ (0.3) (0.8) (0.3) (3) 29 32 49 4.75 to 5.00 11 — — — — 30 26 47 2.75 to 3.00 5 — — — —

TABLE 14 Hard coating layer TiAl complex carbide, carbonitride layer (Ti_(1−x)Al_(x))(C_(y)N_(1−y)) Formation symbol of Area ratio of crystal process of grains having average Average forming crystal grain crystal grain TiAlCN (See misorientation equal Area ratio of width w of Tool body Tables 4 and Content ratio Content ratio of to or greater than 2 cubic crystal crystal Type symbol 5) x_(avg) of Al y_(avg) of C degrees (%) (%) grains (μm) Comparative 16 α A′ 0.68 0.0001 or less 6 97 0.8 coated tools 17 β B′ 0.93 0.0001 or less 9 100 1.1 18 γ C′ 0.70 0.0001 or less 5 98 0.4 19 δ D′ 0.75 0.0001 or less 6 95 0.4 20 α E′ 0.67 0.0001 or less 7 100 0.8 21 β F′ 0.84 0.0045 10 94 0.4 22 γ G′ 0.79 0.0028 5 100 1.0 23 δ H′ 0.60 0.0001 or less 6 100 0.7 24 α I′ 0.91 0.0029 1 75 1.0 25 β J′ 0.91 0.0001 or less 4 66 0.2 26 γ A′ 0.66 0.0001 or less 5 95 0.2 27 δ B′ 0.92 0.0001 or less 6 100 0.9 28 α C′ 0.70 0.0001 or less 8 96 0.7 Reference 29 β AIP 0.49 0.0001 or less 13 100 1.4 coated tool 30 γ AIP 0.60 0.0001 or less 16 100 0.6 Hard coating layer TiAl complex carbide, carbonitride layer (Ti_(1−x)Al_(x))(C_(y)N_(1−y)) Distribution Distribution ratio of ratio of frequencies at frequencies at which inclined which inclined Inclined angles of angles of angle section normal lines of normal lines of in which the {111} planes {111} planes highest peak are present in a are present in a is observed Average range of 0 to 12 range of 0 to 12 in the region TiAl complex carbide, aspect degrees in the degrees in the on the side Target carbonitride layer ratio A of region on the region on the of the layer (Ti_(1−x)Al_(x))(C_(y)N_(1−y)) crystal side of the tool side of the surface thickness First Second Third Fourth Type grains body M_(deg) surface N_(deg) (degrees) (μm) layer layer layer layer Comparative 16 5.2 27 29 33.75 to 12 — — — — coated 34.00 tools 17 2.7 34 43 14.50 to 6 — — — — 14.75 18 0.8 15 18 33.25 to 7 — — — — 33.50 19 1.5 22 17 41.50 to 20 — — — — 41.75 20 5.2 19 23 28.25 to 16 — — — — 28.50 21 2.1 24 19 26.75 to 3 — — — — 27.00 22 3.0 21 24 34.25 to 8 TiN-2 — — — 34.50 (0.7) 23 5.0 25 1 32.00 to 4 TiCN TiN-2 — — 32.25 (0.4) (0.5) 24 1.6 26 22 15.25 to 7 Al₂O₃ — — — 15.50 (2)   25 1.2 34 28 36.25 to 15 TiCN Al₂O₃ — — 36.50 (0.5) (2.5) 26 5.5 1 34 32.75 to 16 TiCO Al₂O₃ — — 33.00 (1)   (2)   27 2.5 33 41 16.50 to 4 TiCNO Al₂O₃ — — 16.75 (0.3) (1)   28 1.2 19 18 31.50 to 9 TiN-2 TiCN TiCNO Al₂O₃ 31.75 (0.3) (0.8) (0.3) (3) Reference 29 1 24 32 29.25 to 11 — — — — coated tool 29.50 30 2.1 18 26 31.25 to 5 — — — — 31.50 (Note) “AIP” indicates a film formed through arc ion plating.

Next, all the aforementioned variety of coated tools, namely coated tools 16 to 30 according to the present invention, Comparative coated tools 16 to 28, and Reference coated tools 29 and 30 were subjected to the following dry high-speed intermittent cutting test of carbon steel and a wet high-speed intermittent cutting test of ductile cast iron in a state in which the coated tools were screw-fixed with fixing jigs at tip ends of cutting tools made of tool steel, and wear width of a flank faces at all the cutting edges were measured.

Cutting condition 1:

Work material: round bar of JIS⋅S45C with four longitudinal grooves at an equal interval in a length direction

Cutting speed: 330 m/min

Depth of cut: 2.0 mm

Feed: 0.3 mm/rev

Cutting time: 5 minutes

(The ordinary cutting speed is 220 m/min)

Cutting condition 2:

Work material: round bar of JIS⋅FCD700 with four longitudinal grooves at an equal interval in a length direction

Cutting speed: 280 m/min

Depth of cut: 2.0 mm

Feed: 0.3 mm/rev

Cutting time: 5 minutes

(The ordinary cutting speed is 200 m/min)

Table 15 shows results of the cutting test.

TABLE 15 Wear width of a flank face Result of cutting (mm) test (minutes) Cutting Cutting Cutting Cutting Type condition 1 condition 2 Type condition 1 condition 2 Coated 16 0.21 0.21 Comparative 16 4.3* 2.5* tools 17 0.21 0.22 coated tools 17 4.7* 4.3* according 18 0.16 0.10 18 2.2* 2.4* to the 19 0.14 0.14 19 2.3* 2.3* present 20 0.22 0.22 20 3.8* 3.9* invention 21 0.10 0.11 21 4.3* 2.8* 22 0.22 0.23 22 4.8* 4.2* 23 0.18 0.13 23 4.3* 4.2* 24 0.23 0.24 24 2.9* 1.9* 25 0.22 0.23 25 2.2* 1.7* 26 0.20 0.19 26 3.6* 4.4* 27 0.19 0.17 27 4.8* 3.8* 28 0.19 0.16 28 3.1* 2.3* 29 0.13 0.14 Reference 29 4.3* 2.5* 30 0.20 0.20 coated tools 30 3.4* 3.6* The * marks in the sections of the comparative coated tools and the reference coated tools denote cutting times (minutes) at which the life end was reached due to the occurrence of chipping.

From the results shown in Tables 9 and 15, hardness is improved due to strain of the crystal grains, and toughness is improved while high wear resistance is maintained in the coated tools according to the present invention, by the predetermined average crystal grain misorientations being present in the crystal grains which have cubic structures which form the layer of a complex nitride or a complex carbonitride of Al and Ti that forms the hard coating layer, and by the inclined angles of the normal lines of the {111} planes having the predetermined inclined angle frequency distribution in the region on the side of the tool body and in the region on the side of the surface of the crystal grains. Further, it is obvious that excellent chipping resistance and fracture resistance are achieved even in a case in which the coated tools are used in a high-speed intermittent cutting in which an intermittent and impact, high load exerts on cutting edges, and as a result, excellent wear resistance is exhibited in use over a long period of time.

In contrast, it is obvious that Comparative coated tools 1 to 13 and 16 to 28 and Reference coated tools 14, 15, 29, and 30 in which the predetermined average crystal grain misorientations are not present in the crystal grains which have cubic structures which form the layer of a complex nitride or a complex carbonitrides of Al and Ti that forms the hard coating layers or in which the inclined angles of the normal lines of the {111} planes do not have the predetermined inclined angle frequency distribution in the region on the side of the tool body and in the region on the side of the surface of the crystal grains end the lifes thereof in short periods of time due to the occurrence of chipping, fracture, and the like in a case in which the coated tools are used in the high-speed intermittent cutting, which is accompanied with high heat generation, in which an intermittent and impact, high load exerts on the cutting edges.

Example 3

WC powder, TiC powder, TaC powder, NbC powder, Cr₃C₂ powder, and Co powder with average grain sizes of 1 to 3 μm were prepared as raw material powder, the raw material powder was mixed together in the mixing compositions shown in Table 16, wax was further added thereto, the mixture was mixed with acetone in a ball mill for 24 hours, was dried in a reduced pressure, and was press-molded into a green compact with a predetermined shape under a pressure of 98 MPa, the green compact is vacuum-sintered under conditions in which it was held in vacuum of 5 Pa at a predetermined temperature within a range of 1370 to 1470° C. for 1 hour, and after the sintering, tool bodies E to G made of WC-based cemented carbide with an insert shape of ISO standard SEEN1203AFSN were respectively manufactured.

TiCN (mass ratio TiC/TiN=50/50) powder, Mo₂C powder, ZrC powder, NbC powder, WC powder, Co powder, and Ni powder with average grain sizes of 0.5 to 2 μm were prepared as raw material powder, the raw material powder was mixed together in the mixing compositions shown in Table 17, the mixture was wet mixed in a ball mill for 24 hours, was dried, and was press-molded into a green compact under a pressure of 98 MPa, the green compact is sintered under conditions in which it was held in nitrogen atmosphere at 1.3 kPa at a temperature of 1500° C. for 1 hour, and after the sintering, a tool body H made of TiCN-based cermet with an insert shape of ISO standard SEEN1203AFSN was manufactured.

Next, a thermal CVD method was performed for on the surfaces of the tool bodies E to H for a predetermined time by using a chemical vapor deposition apparatus under the forming conditions shown in Tables 19 and 20, that is, by using the gas group A consisting of NH₃, N₂, and H₂, the gas group B consisting of TiCl₄, Al(CH₃)₃, AlCl₃, MeCl_(n) (where any of SiCl₄, ZrCl₄, BCl₃, VCl₄, and CrCl₂), N₂, and H₂, and the gas supply method of setting the reaction gas composition (% by volume with respect to the total of the gas group A and the gas group B) to NH₃: 1.0 to 1.5%, N₂: 1.0 to 2.0%, and H₂: 55 to 60% as the gas group A, AlCl₃: 0.6 to 0.9%, TiCl₄: 0.2 to 0.3%, Al(CH₃)₃: 0 to 0.5%, MeCl_(n) (where any of SiCl₄, ZrCl₄, BCl₃, VCl₄, and CrCl₂): 0.1 to 0.2%, N₂: 12.5 to 15.0%, and H₂: the remaining amount as the gas group B, for example, under conditions of a reaction atmosphere pressure: 4.5 to 5.0 kPa, a reaction atmosphere temperature: 700 to 900° C., a supply cycle: 1 to 5 seconds, a gas supply time per cycle: 0.15 to 0.25 seconds, and a supply phase difference between the gas group A and the gas group B: 0.10 to 0.20 seconds, and the hard coating layers, in which the crystal grains which have cubic structures with the average crystal grain misorientations of 2 degrees or greater as shown in Table 22 were present at the area ratios shown in Table 22, which were made of (Ti_(1-x-y)Al_(x)Me_(y))(C_(z)N_(1-z)) layers with the target layer thicknesses shown in Table 22, thereby coated tools 31 to 45 according to the present invention were manufactured.

Note that the lower layers shown in Table 21 and/or the upper layers shown in Table 22 were formed for coated tools 36 to 43 according to the present invention under the forming conditions shown in Table 18.

In addition, for the purpose of comparison, hard coating layers that contained at least layer of a complex nitride or a complex carbonitrides of Ti and Al with the target layer thicknesses (μm) shown in Table 23 were deposited on the surfaces of the tool bodies E to H under the conditions shown in Tables 19 and 20 in a manner similar to that for coated tools 31 to 45 according to the present invention. At this time, Comparative coated tools 31 to 45 were manufactured by forming the hard coating layers such that the reaction gas composition on the surface of the tool bodies did not temporarily change in a process of forming the (Ti_(1-α-β)Al_(α)Me_(β))(C_(γ)N_(1-γ)) layers.

Note that the lower layers shown in Table 21 and/or the upper layers shown in Table 23 were formed for Comparative coated tools 36 to 43 under the forming conditions shown in Table 18 in a manner similar to that for coated tools 36 to 43 according to the present invention.

In addition, a scanning electron microscope (magnification: 5000 times) was used to measure sections in a direction perpendicular to the tool bodies of the respective constituent layers of coated tools 31 to 45 according to the present invention and Comparative coated tools 31 to 45, and layer thicknesses at five points in an observation field of view were measured and averaged to obtain average layer thicknesses. All the layers had average layer thicknesses that were substantially the same as the target layer thicknesses shown in Tables 21 to 23.

In addition, for the average content ratio of Al and an average content ratio of Me in the layer of a complex nitride or a complex carbonitride, the average content ratio α_(avg) of Al and the average content ratio β_(avg) of Me were obtained from averages of obtained analysis results of characteristic X-rays at ten points by irradiating polished surface as a surfaces of the samples with electron beams from the side of the surfaces of the samples by using an electron microanalyzer (EPMA). The average content ratio γ_(avg) of C was obtained by secondary ion mass analysis (SIMS). The ranges of 70 μm×70 μm from the side of the surfaces of the samples were irradiated with ion beams, and concentrations of the components discharged by a sputtering effect were measured in a depth direction. The average content ratio γ_(avg) of C represents an average value in the depth direction of the layer of a complex nitride or a complex carbonitride of Ti, Al, and Me. However, the content ratio of C excludes the content ratio of inevitable C contained even when gas containing C is intentionally not used as a gas raw material. Specifically, the content ratio (atomic ratio) of the C component contained in the layer of a complex nitride or a complex carbonitride in a case in which the supply amount of Al(CH₃)₃ is assumed to be 0 was obtained as the content ratio of inevitable C, and a value obtained by subtracting the content ratio of inevitable C from a content ratio (atomic ratio) of the C component contained in the layer of a complex nitride or a complex carbonitride obtained in a case in which Al(CH₃)₃ was intentionally supplied was obtained as γ_(avg). The results thereof are shown in Tables 22 and 23.

Furthermore, crystal orientations of the individual crystal grains that formed the layer of a complex nitride or a complex carbonitride of Ti, Al, and Me and had cubic structures were analyzed in the vertical sectional direction by using an electron backscatter diffraction apparatus, and in a case in which there were misorientations of 5 degrees or greater between adjacent pixels, the parts were regarded as grain boundaries, a region surrounded by grain boundaries was regarded as one crystal grain, crystal grain misorientations were obtained between a certain pixel in a crystal grain and all the other pixels in the same crystal grain, and the crystal grain misorientations were mapped by dividing a range of 0 to 10 degrees into sections of each 1 degree, that is, a section of equal to or greater than 0 degrees and less than 1 degree, a section of equal to or greater than 1 degree and less than 2 degrees, a section of equal to or greater than 2 degrees and less than 3 degrees, a section of equal to or greater than 3 degrees and less than 4 degrees, and the like. The area ratio of the crystal grains with the average crystal grain misorientations of 2 degrees or greater with respect to the entire layer of a complex nitride or a complex carbonitride of Ti, Al, and Me was obtained from the mapping diagram. The results are shown in Tables 22 and 23.

FIG. 7 shows an example of histogram of the average crystal grain misorientations measured in the coated tool according to the present invention, and FIG. 8 shows an example of histogram of the average crystal grain misorientations measured in the comparative coated tool.

In addition, for inclined angle frequency distribution of the hard coating layer, a section of the hard coating layer formed of the layer of complex carbonitride of Ti, Al, and Me that had cubic structures was placed in a body tube of a field emission-type scanning electron microscope in a state in which the section was polished, the polished surface as a surface was analyzed in a region on the side of the surface of the tool body (tool body) and a region on the side of the surface, which were obtained by equally dividing the polished surface as a surface into two regions in the layer thickness direction, the individual crystal grains that had cubic crystal grain lattice that was present within the measurement ranges were irradiated with electron beams at an acceleration voltage of 10 kV at an incident angle of 70 degrees with an irradiation current of 1 nA, within the measurement ranges of the region on the side of the boundary surface and the region on the side of the surface in the direction perpendicular to the tool body, and for the width of 10 μm for five fields of view at intervals of 0.1 μm/step in the horizontal direction of the tool body, inclined angles of normal lines of {111} planes, which were crystal planes of the crystal grains, with respect to a normal line of the surface of the tool body (a direction perpendicular to the surface of the tool body in the polished section) were measured by using an electron backscatter diffraction image apparatus, measured inclined angles within a range of 0 to 45 degrees from among the measured inclined angles were divided into sections at a pitch of 0.25 degrees on the basis of the measurement results, and frequencies at which the measured inclined angles were present in the respective sections were aggregated, thereby ratio M_(deg) and N_(deg) of frequencies at which the measured inclined angles were present within an angular range in which the highest peak was present in inclined angle sections in the region on the side of the surface and within a range of 0 to 12 degrees were obtained. The results are shown in Tables 22 and 23.

FIG. 9 shows an example of the inclined angle frequency distribution measured in the region on the side of the tool body of the hard coating layer that is formed of the layer of a complex nitride or a complex carbonitride of Ti, Al, and Me of the coated tool according to the present invention, and FIG. 10 shows an example of the inclined angle frequency distribution measured in the region on the side of the surface of the hard coating layer that is formed of the layer of a complex nitride or a complex carbonitride of Ti, Al, and Me of the coated tool according to the present invention.

Further, analysis was performed at intervals of 0.1 μm in the vertical sectional direction by using an electron backscatter diffraction apparatus, measurement within a measurement range with a width of 10 μm and a vertical length of the film thickness in the vertical sectional direction was performed in five fields of view, the total number of pixels that belonged to the crystal grains which had cubic structures that formed the layer of a complex nitride or a complex carbonitride was obtained, and the area ratio of the crystal grains which had cubic structures that had the layer of a complex nitride or a complex carbonitride was obtained from a ratio with respect to the total number of measured pixels in the measurement performed on the hard coating layer in the aforementioned five fields of view. The results are shown in Tables 22 and 23.

Further, the individual crystal grains in the (Ti_(1-x-y)Al_(x)Me_(y))(C_(z)N_(1-z)) layers that were present within a range at the length of 10 μm in the horizontal direction of the surface of the tool bodies and that formed the layer of a complex nitride or a complex carbonitrides of Ti, Al, and Me in coated tools 31 to 45 according to the present invention and Comparative coated tools 31 to 45 were observed from the side of the film sections perpendicular to the surfaces of the tool bodies by using a scanning electron microscope (magnitude of 5000 times or 20000 times) in the section direction perpendicular to the tool bodies, the crystal grain widths w in the direction parallel to the surfaces of the bodies and the crystal grain lengths l in the direction perpendicular to the surfaces of the bodies were measured, aspect ratios a (=l/w) of the respective crystal grains were calculated, an average value of the aspect ratios a obtained for the individual crystal grains was calculated as an average aspect ratio A, and an average value of the crystal grain widths w obtained for the individual crystal grains was calculated as an average crystal grain width W. The results are shown in Tables 22 and 23.

TABLE 16 Mixing composition (% by mass) Type Co TiC TaC NbC Cr₃C₂ WC Tool E 8.0 1.5 — 3.0 0.4 Remainder body F 8.5 — 1.8 0.2 — Remainder G 7.0 — — — — Remainder

TABLE 17 Mixing composition (% by mass) Type Co Ni ZrC NbC Mo₂C WC TiCN Tool H 8 5 1 6 6 10 Remainder body

TABLE 18 Forming conditions (pressure of reaction atmosphere indicates Constituent layer of hard coating layer kPa and temperature indicates ° C.)Forming conditions Formation Reaction atmosphere Type symbol Reaction gas composition (% by volume) Pressure Temperature (Ti_(1−α−β)Al_(α)Me_(β))(C_(γ)N_(1-γ)) layer See Tables 19 and 20 Ti compound TiC TiC TiCl₄: 2%, CH₄: 10%, H₂: remainder 7 850 layer TiN TiN TiCl₄: 4.2%, N₂: 30%, H₂: remainder 30 780 TiCN TiCN TiCl₄: 2%, CH₃CN: 0.7%, N₂: 10%, H₂: remainder 7 780 TiCO TiCO TiCl₄: 4.2%, CO: 4%, H₂: remainder 7 850 TiCNO TiCNO TiCl₄: 2%, CH₃CN: 0.7%, N₂: 10%, CO₂: 0.3%, H₂: remainder 13 780 Al₂O₃ layer Al₂O₃ Al₂O₃ AlCl₃: 2.2%, CO₂: 5.5%, HCl: 2.2%, H₂S: 0.8%, H₂: remainder 7 800

TABLE 19 Formation of hard coating layer Forming conditions (reaction gas composition is For- represented as ratio with respect to a total for the gas group A and the gas group B.) Process mation Reaction gas group A type symbol composition (% by volume) Reaction gas group B composition (% by volume) Film Si-A NH₃: 1.4% N₂: 1.3% H₂: 58% AlCl₃: 0.7% TiCl₄: 0.3% SiCl₄: 0.1% N₂: 13.0% Al(CH₃)₃: 0.5% H₂: remainder forming Si-B NH₃: 1.0% N₂: 1.7% H₂: 55% AlCl₃: 0.8% TiCl₄: 0.2% SiCl₄: 0.1% N₂: 14.5% Al(CH₃)₃: 0% H₂: remainder process Si-C NH₃: 1.3% N₂: 1.5% H₂: 60% AlCl₃: 0.9% TiCl₄: 0.3% SiCl₄: 0.2% N₂: 12.5% Al(CH₃)₃: 0% H₂: remainder according Zr-A NH₃: 1.2% N₂: 1.8% H₂: 56% AlCl₃: 0.8% TiCl₄: 0.2% ZrCl₄: 0.2% N₂: 14.0% Al(CH₃)₃: 0% H₂: remainder to the Zr-B NH₃: 1.5% N₂: 1.0% H₂: 57% AlCl₃: 0.9% TiCl₄: 0.2% ZrCl₄: 0.1% N₂: 13.0% Al(CH₃)₃: 0% H₂: remainder present Zr-C NH₃: 1.3% N₂: 1.9% H₂: 55% AlCl₃: 0.6% TiCl₄: 0.3% ZrCl₄: 0.1% N₂: 15.0% Al(CH₃)₃: 0.2% H₂: remainder invention B-A NH₃: 1.1% N₂: 1.6% H₂: 59% AlCl₃: 0.7% TiCl₄: 0.2% BCl₃: 0.1% N₂: 13.5% Al(CH₃)₃: 0% H₂: remainder B-B NH₃: 1.3% N₂: 2.0% H₂: 57% AlCl₃: 0.8% TiCl₄: 0.3% BCl₃: 0.2% N₂: 14.0% Al(CH₃)₃: 0.2% H₂: remainder B-C NH₃: 1.4% N₂: 1.5% H₂: 58% AlCl₃: 0.7% TiCl₄: 0.3% BCl₃: 0.1% N₂: 12.5% Al(CH₃)₃: 0% H₂: remainder V-A NH₃: 1.5% N₂: 1.2% H₂: 56% AlCl₃: 0.8% TiCl₄: 0.2% VCl₄: 0.1% N₂: 13.5% Al(CH₃)₃: 0% H₂: remainder V-B NH₃: 1.2% N₂: 1.7% H₂: 60% AlCl₃: 0.9% TiCl₄: 0.3% VCl₄: 0.1% N₂: 13.0% Al(CH₃)₃: 0.5% H₂: remainder V-C NH₃: 1.0% N₂: 1.1% H₂: 58% AlCl₃: 0.7% TiCl₄: 0.3% VCl₄: 0.2% N₂: 15.0% Al(CH₃)₃: 0% H₂: remainder Cr-A NH₃: 1.4% N₂: 1.4% H₂: 59% AlCl₃: 0.6% TiCl₄: 0.3% CrCl₂: 0.2% N₂: 14.0% Al(CH₃)₃: 0% H₂: remainder Cr-B NH₃: 1.3% N₂: 1.0% H₂: 56% AlCl₃: 0.8% TiCl₄: 0.3% CrCl₂: 0.1% N₂: 14.5% Al(CH₃)₃: 0% H₂: remainder Cr-C NH₃: 1.3% N₂: 1.8% H₂: 57% AlCl₃: 0.7% TiCl₄: 0.2% CrCl₂: 0.1% N₂: 13.5% Al(CH₃)₃: 0% H₂: remainder Compar- Si-a NH₃: 1.2% N₂: 3.0% H₂: 58% AlCl₃: 0.8% TiCl₄: 0.3% SiCl₄: 0.4% N₂: 13.0% Al(CH₃)₃: 0% H₂: remainder ative Si-b NH₃: 1.5% N₂: 1.5% H₂: 65% AlCl₃: 0.4% TiCl₄: 0.3% SiCl₄: 0.1% N₂: 15.0% Al(CH₃)₃: 0.2% H₂: remainder film Si-c NH₃: 0.6% N₂: 2.0% H₂: 55% AlCl₃: 0.7% TiCl₄: 0.2% SiCl₄: 0.2% N₂: 11.0% Al(CH₃)₃: 0% H₂: remainder forming Zr-a NH₃: 1.4% N₂: 1.2% H₂: 59% AlCl₃: 0.9% TiCl₄: 0.1% ZrCl₄: N₂: 14.5% Al(CH₃)₃: 0% H₂: remainder process 0.05% Zr-b NH₃: 1.0% N₂: 0.7% H₂: 57% AlCl₃: 0.5% TiCl₄: 0.4% ZrCl₄: 0.2% N₂: 12.5% Al(CH₃)₃: 0% H₂: remainder Zr-c NH₃: 1.3% N₂: 1.7% H₂: 47% AlCl₃: 0.6% TiCl₄: 0.3% ZrCl₄: 0.1% N₂: 14.0% Al(CH₃)₃: 0.7% H₂: remainder B-a NH₃: 1.3% N₂: 1.8% H₂: 58% AlCl₃: 0.7% TiCl₄: 0.2% BCl₃: 0.3% N₂: 17.5% Al(CH₃)₃: 0% H₂: remainder B-b NH₃: 2.0% N₂: 1.3% H₂: 60% AlCl₃: 0.8% TiCl₄: 0.1% BCl₃: 0.1% N₂: 13.0% Al(CH₃)₃: 0% H₂: remainder B-c NH₃: 1.1% N₂: 1.1% H₂: 56% AlCl₃: 1.2% TiCl₄: 0.2% BCl₃: 0.2% N₂: 14.0% Al(CH₃)₃: 0.5% H₂: remainder V-a NH₃: 1.8% N₂: 2.5% H₂: 50% AlCl₃: 0.9% TiCl₄: 0.3% VCl₄: 0.1% N₂: 13.5% Al(CH₃)₃: 0% H₂: remainder V-b NH₃: 1.4% N₂: 1.4% H₂: 59% AlCl₃: 0.8% TiCl₄: 0.2% VCl₄: 0.03% N₂: 20.0% Al(CH₃)₃: 0% H₂: remainder V-c NH₃: 1.2% N₂: 1.0% H₂: 60% AlCl₃: 0.6% TiCl₄: 0.5% VCl₄: 0.1% N₂: 15.0% Al(CH₃)₃: 1.0% H₂: remainder Cr-a NH₃: 1.5% N₂: 2.0% H₂: 70% AlCl₃: 0.7% TiCl₄: 0.3% CrCl₂: 0.2% N₂: 10.0% Al(CH₃)₃: 0% H₂: remainder Cr-b NH₃: 0.8% N₂: 1.6% H₂: 55% AlCl₃: 1.4% TiCl₄: 0.2% CrCl₂: 0.1% N₂: 13.5% Al(CH₃)₃: 0% H₂: remainder Cr-c NH₃: 1.0% N₂: 0.3% H₂: 57% AlCl₃: 0.7% TiCl₄: 0.2% CrCl₂: 0.3% N₂: 14.5% Al(CH₃)₃: 0% H₂: remainder

TABLE 20 Forming conditions (pressure of reaction atmosphere indicates kPa and temperature indicates ° C.) Phase difference Gas group A Gas group B in supply Formation of hard Supply Supply between coating layer Supply time per Supply time per gas group Formation cycle cycle cycle cycle A and gas Reaction Atmosphere Process type symbol (seconds) (seconds) (seconds) (seconds) group B Pressure Temperature Film Si-A 3 0.20 3 0.20 0.15 4.7 800 forming Si-B 4 0.25 4 0.25 0.20 5.0 900 process Si-C 5 0.25 5 0.25 0.20 4.7 750 according to Zr-A 2 0.15 2 0.15 0.10 4.5 800 the present Zr-B 4 0.20 4 0.20 0.15 4.5 850 invention Zr-C 1 0.15 1 0.15 0.10 5.0 700 B-A 3 0.20 3 0.20 0.15 4.5 900 B-B 1 0.15 1 0.15 0.10 4.7 750 B-C 5 0.25 5 0.25 0.20 5.0 800 V-A 3 0.20 3 0.20 0.15 4.7 800 V-B 4 0.20 4 0.20 0.15 4.7 750 V-C 5 0.25 5 0.25 0.20 4.5 700 Cr-A 2 0.15 2 0.15 0.10 5.0 850 Cr-B 4 0.20 4 0.20 0.15 4.7 800 Cr-C 3 0.20 3 0.20 0.15 4.5 800 Comparative Si-a — — — — — 6.0 600 film forming Si-b — — — — — 5.0 900 process Si-c — — — — — 4.5 850 Zr-a — — — — — 4.7 750 Zr-b — — — — — 4.7 650 Zr-c — — — — — 4.0 800 B-a — — — — — 4.5 700 B-b — — — — — 5.0 800 B-c — — — — — 4.7 950 V-a — — — — — 3.5 800 V-b — — — — — 4.7 850 V-c — — — — — 4.5 750 Cr-a — — — — — 5.5 700 Cr-b — — — — — 4.7 800 Cr-c — — — — — 5.0 950

TABLE 21 Hard coating layer (Numerical values in the lower sections represent target average layer thicknesses (μm) of the layer.) Lower layer First Second Third Type layer layer layer Coated tools according 31 — — — to the present 32 — — — invention/Comparative 33 — — — coated tools 34 — — — 35 — — — 35 TiC — — (0.3) 37 TiN — — (0.5) 38 TiN TiCN — (0.1) (1) 39 TiN TiCN — (0.1) (3) 40 TiN — — (0.3) 41 TiN TiCN — (0.5) (2) 42 TiN TiCN — (0.3) (1) 43 TiN — — (0.5) 44 — — — 45 — — —

TABLE 22 Hard coating layer TiAlMe complex carbonitride layer (T_(1−α−β)Al_(α)Me_(β))(C_(γ)N_(1−γ)) Formation symbol of Area ratio of crystal process of Sum of grains having forming average average crystal grain Tool TiAlMeCN Content Content content ratios Average misorientation equal body (See Tables 4 ratio X_(avg) of ratio of Y_(avg) of Al and Me content to or greater than 2 Type symbol and 5) Al of Me X_(avg) + Y_(avg) ratio Z_(avg) of C degrees (%) Coated tool 31 E Si-A 0.67 0.031 0.701 0.0048 48 according 32 F Si-B 0.77 0.054 0.824 0.0001 or 69 to the less present 33 G Si-C 0.79 0.076 0.866 0.0001 or 42 invention less 34 H Zr-A 0.86 0.089 0.949 0.0001 or 45 less 35 E Zr-B 0.92 0.018 0.938 0.0001 or 62 less 38 F Zr-C 0.61 0.046 0.656 0.0019 22 37 G B-A 0.84 0.049 0.889 0.0001 or 58 less 38 H B-B 0.75 0.082 0.832 0.0011 26 39 E B-C 0.69 0.020 0.710 0.0001 or 64 less 40 F V-A 0.89 0.023 0.913 0.0001 or 49 less 41 G V-B 0.80 0.008 0.808 0.0036 38 42 H V-C 0.65 0.085 0.735 0.0001 or 36 less 43 E Cr-A 0.63 0.097 0.727 0.0001 or 43 less 44 F Cr-B 0.74 0.013 0.753 0.0001 or 47 less 45 G Cr-C 0.86 0.045 0.905 0.0001 or 40 less Hard coating layer TiAlMe complex carbonitride layer (T_(1−α−β)Al_(α)Me_(β))(C_(γ)N_(1−γ)) Distribution ratio of Distribution frequencies at ratio of which frequencies at inclined which angles of inclined Inclined normal lines angles of angle of {111} normal lines section in Upper layer planes are of {111} which the Average (Numerical values in present in a planes are highest peak crystal the lower sections range of 0 to present in a is observed Area grain Average represent target 12 degrees in range of 0 to in the region ratio width W aspect average layer the region on 12 degrees in on the side of of cubic ratio A Target thickness (μm) of the the side of the the region on of the cubic crystal of cubic layer layer.) tool body the side of the surface crystal grains crystal thickness First Second Type M_(deg) surface N_(deg) (degrees) (%) (μm) grains (μm) layer layer Coated tool 31 24 41 9.75 to 10.0  91 0.8 4.8 4 — — according 32 19 48 7.5 to 7.75 94 1.1 4.3 5 — — to the present 33 39 53 4.5 to 4.75 83 1.6 3.0 5 — — invention 34 34 50 4.0 to 4.25 62 0.3 5.7 3 — — 35 11 36 10.0 to 10.25 59 0.08 15.8 4 — — 38 39 56 3.25 to 3.5  96 2.3 2.6 6 — — 37 23 46 8.0 to 8.25 96 0.4 9.3 4 — — 38 39 51 3.75 to 4.0  92 1.7 1.5 3 — — 39 21 47 6.25 to 6.5  100 0.7 5.3 4 — — 40 27 44 8.5 to 8.75 80 0.05 12.9 2 TiCN Al₂O₃ (0.5) (2) 41 38 62 0.75 to 1.0  78 2.1 1.3 3 TiCNO Al₂O₃ (0.2) (1) 42 35 58 2.75 to 3.0  88 1.4 1.2 2 TiCO Al₂O₃ (0.3) (2) 43 16 34 11.5 to 11.75 77 0.5 1.9 2 TiCNO Al₂O₃ (0.3) (3) 44 25 45 7.0 to 7.25 100 1.2 2.3 3 — — 45 33 48 5.0 to 5.25 85 0.9 5.0 5 — —

TABLE 23 Hard coating layer TiAlMe complex carbonitride layer (T1 − α − βAlαMeβ)(CγN1 − γ) Distribution Area ratio of ratio of frequencies at crystal which grains inclined having angles of average normal lines Formation crystal of {111} symbol grain planes are of process misorientation present in a of Sum of equal to range of 0 to forming average or 12 degrees in TiAlMeCN Content content greater the region on Tool (See ratio of ratios of Al Average than 2 the side of the body Tables 4 Content ratio Y_(avg) of and Me X_(avg) + content ratio degrees tool body Type symbol and 5) X_(avg) of Al Me Y_(avg) Z_(avg) of C (%) M_(deg) Comparative 31 E Si-a 0.73 0.137 0.867 0.0001 or 9 54 coated less tools 32 F Si-b 0.56 0.056 0.616 0.0017 2 37 33 G Si-c 0.86 0.097 0.957 0.0001 or 0 24 less 34 H Zr-a 0.99 0.003 0.993 0.0001 or — — less 35 E Zr-b 0.52 0.089 0.609 0.0001 or 1 67 less 36 F Zr-c 0.61 0.047 0.657 0.0077 3 47 37 G B-a 0.84 0.113 0.953 0.0001 or 0 29 less 38 H B-b 0.98 0.019 0.999 0.0001 or — — less 39 E B-c 0.96 0.038 0.998 0.0045 — — 40 F V-a 0.79 0.007 0.797 0.0001 or 0 31 less 41 G V-b 0.89 0.002 0.892 0.0001 or 3 39 less 42 H V-c 0.53 0.013 0.543 0.0111 4 59 43 E Cr-a 0.66 0.086 0.746 0.0001 or 1 49 less 44 F Cr-b 0.98 0.004 0.984 0.0001 or 0 25 less 45 G Cr-c 0.83 0.106 0.936 0.0001 or 0  7 less Hard coating layer TiAlMe complex carbonitride layer (T1 − α − βAlαMeβ)(CγN1 − γ) Distribution ratio of frequencies at which inclined Inclined angles of angle normal lines section in of {111} which the Average planes are highest peak crystal Upper layer (Numerical present in a is observed grain Average values in the lower range of 0 to in the region width W aspect sections represent 12 degrees in on the side of cubic ratio A of Target target average the region on of the Area ratio crystal cubic layer layer thickness the side of the surface of cubic grains crystal thickness (μm) of the layer.) Type surface N_(deg) (degrees) crystal (%) (μm) grains (μm) First layer Second layer Comparative 31 62 2.5 to 2.75 89 1.7 2.3 4 — — coated tools 32 37 11.0 to 11.25 97 0.2 19.6 5 — — 33 24 16.75 to 17.0  68 0.07 1.8 5 — — 34 — — 0 — — 3 — — 35 68 1.5 to 1.75 100 1.5 2.5 4 — — 36 50 5.0 to 5.25 81 1.0 3.3 6 — — 37 28 27.25 to 27.5  43 0.8 2.3 4 — — 38 — — 0 — — 3 — — 39 — — 0 — — 4 — — 40 30 19.75 to 20.0  100 0.05 9.8 0.5 TiCN Al₂O₃ (0.5) (2) 41 44 8.5 to 8.75 96 0.3 6.1 3 TiCNO Al₂O₃ (0.2) (1) 42 65 2.75 to 3.0  73 2.4 0.7 2 TiCO Al₂O₃ (0.3) (2) 43 51 6.0 to 6.25 99 1.2 0.8 2 TiCNO Al₂O₃ (0.3) (3) 44 21 22.5 to 22.75 17 0.1 1.5 3 — — 45 13 31.5 to 31.75 40 0.06 22.4 5 — — (Note) Only hexagonal crystals were observed and no cubic crystals were observed in Comparative coated tools 34, 38, and 39.

Next, all the aforementioned variety of coated tools, namely coated tools 31 to 45 according to the present invention and Comparative coated tools 31 to 45 were subjected to the following dry high-speed face milling and a center cutting machining test, which are types of high-speed intermittent cutting of alloy steel, in a state in which the coated tools were clamped with fixing jigs at tip ends of cutters made of tool steel with a cutter diameter of 125 mm, and wear width of a flank faces at all the cutting edges were measured. The results are shown in Table 24.

Tool body: tungsten-carbide-based cemented carbide, titanium-carbonitride-based cermet Cutting test: dry-type high-speed face milling, center cutting machining

Work material: block material of JIS⋅S55C with a width of 100 mm and a length of 400 mm

Rotation speed: 713 min⁻¹

Cutting speed: 280 m/min

Depth of cut: 2.5 mm

Feed rate per tooth: 0.30 mm/tooth

Cutting time: 8 minutes

TABLE 24 Wear width Cutting of a flank test result Type face (mm) Type (minutes) Coated tools 31 0.17 Comparative 31 3.8* according to 32 0.13 coated 32 5.9* the present 33 0.14 tools 33 4.1* invention 34 0.15 34 1.7* 35 0.16 35 3.3* 36 0.12 36 4.4* 37 0.13 37 1.9* 38 0.08 38 2.0* 39 0.11 39 1.6* 40 0.10 40 7.2* 41 0.07 41 6.8* 42 0.10 42 5.2* 43 0.12 43 6.4* 44 0.14 44 4.8* 45 0.15 45 3.7* The * marks in the sections of the comparative coated tools denote cutting times (minutes) at which life end was reached due to the occurrence of chipping.

Example 4

WC powder, TiC powder, ZrC powder, TaC powder, NbC powder, Cr₃C₂ powder, TiN powder, and Co powder with average grain sizes of 1 to 3 μm were prepared as raw material powder, the raw material powder was mixed together in the mixing compositions shown in Table 25, wax was further added thereto, the mixture was mixed with acetone in a ball mill for 24 hours, was dried in a reduced pressure, and was press-molded into a green compact with a predetermined shape under a pressure of 98 MPa, the green compact is vacuum-sintered under conditions in which it was held in vacuum of 5 Pa at a predetermined temperature within a range of 1370 to 1470° C. for 1 hour, and after the sintering, tool bodies ε to η made of WC-based cemented carbide with an insert shape of ISO standard CNMG120412 were respectively manufactured by performing honing machining at R: 0.07 mm on cutting edge portions.

TiCN (mass ratio TiC/TiN=50/50) powder, NbC powder, WC powder, Co powder, and Ni powder with average grain sizes of 0.5 to 2 μm were prepared as raw material powder, the raw material powder was mixed together in the mixing compositions shown in Table 26, the mixture was wet mixed in a ball mill for 24 hours, was dried, and was press-molded into a green compact under a pressure of 98 MPa, the green compact is sintered under conditions in which it was held in nitrogen atmosphere at 1.3 kPa at a temperature of 1500° C. for 1 hour, and after the sintering, a tool body θ made of TiCN-based cermet with an insert shape of ISO standard CNMG120412 was manufactured by performing honing machining at R: 0.09 mm on a cutting edge portion.

Next, coated tools 46 to 60 according to the present invention shown in Table 28 were manufactured by using a chemical vapor deposition apparatus on the surfaces of these tool bodies ε to η and the tool body θ to deposit hard coating layers with target layer thicknesses, which included at least (Ti_(1-x-y)Al_(x)Me_(y))(C_(z)N_(1-z)), under the conditions shown in Tables 19 and 20 by a method similar to that in Example 1.

Note that the lower layers shown in Table 27 and/or the upper layers shown in Table 28 were formed for coated tools 49 to 58 according to the present invention under the forming conditions shown in Table 18.

In addition, for the purpose of comparison, Comparative coated tools 46 to 60 shown in Table 29 were manufactured by using a chemical vapor deposition apparatus on the surfaces of these tool bodies E to and the tool body θ to deposit hard coating layers with target layer thicknesses shown in Table 29 under the conditions shown in Tables 19 and 20 by a method similar to that for the coated tools according to the present invention.

Note that the lower layers shown in Table 27 and/or the upper layers shown in Table 29 were formed for Comparative coated tools 49 to 58 under the forming conditions shown in Table 18 in a manner similar to that for coated tools 49 to 58 according to the present invention.

In addition, a scanning electron microscope (magnification: 5000 times) was used to measure sections of the respective constituent layers of coated tools 46 to 60 according to the present invention and Comparative coated tools 46 to 60, and layer thicknesses at five points in an observation field of view were measured and averaged to obtain average layer thicknesses. All the layers had average layer thicknesses that were substantially the same as the target layer thicknesses shown in Tables 27 to 29.

In addition, average content ratios α_(avg) of Al, average content ratios β_(avg) of Me, average content ratios γ_(avg) of C, inclined angle frequency distributions M_(deg) on the side of the tool bodies, inclined angle frequency distributions N_(deg) on the side of the front, angular ranges in which the highest peaks were present in inclined angle sections in the regions on the side of the front, average crystal grain widths W and average aspect ratios A of the crystal grains, and area ratios of cubic crystal phases in the crystal grains in the hard coating layers of coated tools 46 to 60 according to the present invention and Comparative coated tools 46 to 60 were obtained by a method similar to that shown in Example 3. The results are shown in Tables 28 and 29.

Furthermore, crystal orientations of the individual crystal grains which had cubic structures that formed the layer of a complex nitride or a complex carbonitride of Ti and Al were analyzed in the vertical sectional direction by using an electron backscatter diffraction apparatus, and crystal grain misorientations were mapped by dividing a range of 0 to 10 degrees into sections of each 1 degree, that is, a section of equal to or greater than 0 degrees and less than 1 degree, a section of equal to or greater than 1 degree and less than 2 degrees, a section of equal to or greater than 2 degrees and less than 3 degrees, a section of equal to or greater than 3 degrees and less than 4 degrees, and the like. Average crystal grain misorientations and an area ratio of the crystal grains with the average crystal grain misorientations of 2 degrees or greater with respect to the entire layer of a complex nitride or a complex carbonitride of Ti, Al, and Me was obtained from the mapping diagram. The results are shown in Tables 28 and 29.

TABLE 25 Mixing composition (% by mass) Type Co TiC ZrC TaC NbC Cr₃C₂ TiN WC Tool ε 6.5 — 1.5 — 2.9 0.1 1.5 Remainder body ξ 7.6 2.6 — 4.0 0.5 — 1.1 Remainder η 6.0 — — — — — — Remainder

TABLE 26 Mixing composition (% by mass) Type Co Ni NbC WC TiCN Tool θ 11 4 6 15 Remainder body

TABLE 27 Lower layer (Numerical values in the lower sections represent target average layer thickness (μm) of the layer.) First Second Third Fourth Type layer layer layer layer Coated tools 46 — — — — according to 47 — — — — the present 48 — — — — invention/ 49 TiC — — — Comparative (0.5) coated tools 50 TiN — — — (0.3) 51 TiN TiCN — — (0.5) (7) 52 TiN TiCN TiN — (0.1) (8) (0.7) 53 TiN TiCN — — (0.3) (10)  54 — — — — 55 TiN TiCN — — (0.5) (6) 56 TiC TiN — — (0.5)   (0.5) 57 TiN TiCN — (0.3) (8) 58 TiN TiCN — (0.1) (4) 59 — — — — 60 — — — —

TABLE 28 Hard coating layer TiAlMe complex carbonitride layer (Ti_(1−α−β)Al_(α)Me_(β))(C_(γ)N_(1−γ)) Distribution ratio of Distribution frequencies ratio of at which frequencies inclined at which angles of inclined normal angles of lines of normal lines {111} of {111} Area ratio of planes are planes are Formation crystal grains present in a present in a symbol of having range of 0 range of 0 process of average to 12 to 12 forming Sum of crystal grain degrees in degrees in TiAlMeCN Content average Average misorientation the region the region Tool (See Content ratio of content ratios content equal to or on the side on the side body Tables 4 ratio X_(avg) Y_(avg) of of Al and Me ratio Z_(avg) greater than 2 of the tool of the Type symbol and 5) of Al Me X_(avg) + Y_(avg) of C degrees (%) body M_(deg) surface N_(deg) Coated 46 ε Si-A 0.68 0.027 0.707 0.0046 52 22 42 tools 47 ξ Si-B 0.79 0.051 0.841 0.0001 or 66 17 45 according less to the 48 η Si-C 0.77 0.072 0.842 0.0001 or 45 36 50 present less invention 49 θ Zr-A 0.85 0.085 0.935 0.0001 or 41 37 50 less 50 ε Zr-B 0.93 0.013 0.943 0.0001 or 58 10 34 less 51 ξ Zr-C 0.62 0.044 0.664 0.0023 21 38 54 52 η B-A 0.86 0.047 0.907 0.0001 or 55 20 42 less 53 θ B-B 0.77 0.080 0.850 0.0017 29 37 52 54 ε B-C 0.67 0.017 0.687 0.0001 or 61 22 49 less 55 ξ V-A 0.91 0.026 0.936 0.0001 or 52 24 43 less 56 η V-B 0.79 0.006 0.796 0.0039 36 35 64 57 θ V-C 0.67 0.082 0.752 0.0001 or 41 33 56 less 58 ε Cr-A 0.60 0.094 0.694 0.0001 or 47 14 36 less 59 ξ Cr-B 0.77 0.011 0.781 0.0001 or 46 27 43 less 60 η Cr-C 0.87 0.042 0.912 0.0001 or 37 35 46 less Hard coating layer TiAlMe complex carbonitride layer (Ti_(1−α−β)Al_(α)Me_(β))(C_(γ)N_(1−γ)) Inclined angle section in which the highest Average peak is crystal observed grain Average in the Area width W aspect Upper layer (Numerical values in the region on ratio of of cubic ratio A of Target lower sections represent target average the side of cubic crystal cubic layer layer thicknesses (μm) of the layer.) the surface crystal grains crystal thickness First Second Third Fourth Type (degrees) (%) (μm) grains (μm) layer layer layer layer Coated 46 9.25 to 9.5  93 0.7 13.5 19 — — — — tools 47 8.0 to 8.25 95 1.3 6.6 14 — — — — according to the 48 4.25 to 4.5  80 1.4 8.6 16 — — — — present invention 49 3.75 to 4.0  64 0.2 6.3 12 — — — — 50 10.5 to 10.75 61 0.09 14.9 10 — — — — 51 3.5 to 3.75 98 2.5 1 8 — — — — 52 8.75 to 9.0  94 0.3 17.4 9 TiN — — — (0.5) 53 3.75 to 4.0  91 1.5 6.0 10 TiN TiCN TiN — (0.3) (0.4) (0.3) 54 5.5 to 5.75 100 0.8 7.4 7 TiCNO Al₂O₃ — — (0.3) (3) 55 8.0 to 8.25 82 0.06 11.7 6 TiCN Al₂O₃ — — (0.5) (3) 56 1.0 to 1.25 75 2.0 1.8 7 TiCO Al₂O₃ — — (0.5) (4) 57 2.25 to 2.5  86 1.6 4.3 9 TiCNO Al₂O₃ — — (0.3) (5) 58 11.0 to 11.25 79 0.6 9.6 10 TiN TiCN TiCNO Al₂O₃ (0.3) (0.5) (0.3) (3) 59 7.5 to 7.75 100 1.1 5.2 13 — — — — 60 5.5 to 5.75 84 0.7 16.8 17 — — — —

TABLE 29 Hard coating layer TiAlMe complex carbonitride layer (Ti_(1−α−β)Al_(α)Me_(β))(C_(γ)N_(1−γ)) Distribution Distribution ratio of ratio of frequencies frequencies at which at which inclined inclined angles of angles of normal normal lines of lines of {111} {111} planes are planes are Area ratio of present in a present in a Formation Sum of crystal grains range of 0 range of 0 symbol of average having average to 12 to 12 process of content crystal grain degrees in degrees in forming Content ratios of Average misorientation the region the region Tool TiAlMeCN Content ratio of Al and Me content equal to or on the side on the side body (See Tables ratio X_(avg) Y_(avg) of X_(avg) + ratio Z_(avg) greater than 2 of the tool of the Type symbol 4 and 5) of Al Me Y_(avg) of C degrees (%) body M_(deg) surface N_(deg) Comparative 46 ε Si-a 0.76 0.129 0.889 0.0001 or 8 55 60 coated tools less 47 ξ Si-b 0.54 0.062 0.602 0.0023 4 35 36 48 η Si-c 0.87 0.093 0.963 0.0001 or 0 22 22 less 49 θ Zr-a 0.99 0.005 0.995 0.0001 or — — — less 50 ε Zr-b 0.53 0.092 0.622 0.0001 or 2 65 66 less 51 ξ Zr-c 0.63 0.041 0.671 0 2 48 48 52 η B-a 0.85 0.118 0.968 0.0001 or 0 24 21 less 53 θ B-b 0.99 0.008 0.998 0.0001 or — — — less 54 ε B-c 0.97 0.027 0.997 0.0041 — — — 55 ξ V-a 0.78 0.006 0.786 0.0001 or 0 28 28 less 56 η V-b 0.91 0.001 0.911 0.0001 or 5 41 43 less 57 θ V-c 0.54 0.019 0.559 0 6 55 57 58 ε Cr-a 0.67 0.080 0.750 0.0001 or 2 50 51 less 59 ξ Cr-b 0.97 0.003 0.973 0.0001 or 0 20 27 less 60 η Cr-c 0.85 0.109 0.959 0.0001 or 0  5  8 less Hard coating layer TiAlMe complex carbonitride layer (Ti_(1−α−β)Al_(α)Me_(β))(C_(γ)N_(1−γ)) Inclined angle section in which the highest Average peak is crystal observed grain in the width Average region on Area W of aspect Upper layer (Numerical values in the the side of ratio of cubic ratio A Target lower sections represent target average the cubic crystal of cubic layer layer thicknesses (μm) of the layer.) surface crystal grains crystal thickness First Second Third Fourth Type (degrees) (%) (μm) grains (μm) layer layer layer layer Comparative 46 2.0 to 2.25 85 1.5 7.7 22 — — — — coated tools 47 11.5 to 11.75 94 0.3 17.4  14 — — — — 48 17.25 to 17.5  58  0.05 1.5 16 — — — — 49 — 0 — — 12 — — — — 50 0.75 to 1.0  100 1.8 5.4 10 — — — — 51 5.5 to 5.75 84 1.4 2.7 8 — — — — 52 21.25 to 21.5  37 0.9 1.9 9 TiN — — — (0.5) 53 — 0 — — 10 TiN TiCN TiN — (0.3) (0.4) (0.3) 54 — 0 — — 7 TiCNO Al₂O₃ — — (0.3) (3) 55 23.0 to 23.25 100  0.08 21.1  6 TiCN Al₂O₃ — — (0.5) (3) 56 8.75 to 9.0  88 0.5 5.2 7 TiCO Al₂O₃ — — (0.5) (4) 57 2.5 to 2.75 69 2.2 1.7 9 TiCNO Al₂O₃ — — (0.3) (5) 58 4.75 to 5.0  97 1.1 6.8 10 TiN TiCN TiCNO Al₂O₃ (0.3) (0.5) (0.3) (3) 59 25.25 to 25.5  26 0.1 1.3 13 — — — — 60 28.5 to 28.75 37  0.05 25.0  17 — — — — (Note) Only hexagonal crystals were observed and no cubic crystals were observed in Comparative coated tools 49, 53, and 54.

Next, all the aforementioned variety of coated tools, namely coated tools 46 to 60 according to the present invention and Comparative coated tools 46 to 60 were subjected to the following dry high-speed intermittent cutting test of carbon steel and a wet high-speed intermittent cutting test of ductile cast iron in a state in which the coated tools were screw-fixed with fixing jigs at tip ends of cutting tools made of tool steel, and wear width of a flank faces at all the cutting edges were measured.

Cutting condition 1:

Work material: round bar of JIS⋅S15C with four longitudinal grooves at an equal interval in a length direction

Cutting speed: 300 m/min

Depth of cut: 2.5 mm

Feed: 0.30 mm/rev

Cutting time: 5 minutes

(The ordinary cutting speed is 220 m/min)

Cutting condition 2:

Work material: round bar of JIS⋅FCD450 with four longitudinal grooves at an equal interval in a length direction

Cutting speed: 280 m/min

Depth of cut: 2.0 mm

Feed: 0.30 mm/rev

Cutting time: 5 minutes

(The ordinary cutting speed is 250 m/min)

Table 30 shows results of the cutting test.

TABLE 30 Wear width of a flank Cutting test result face (mm) (minutes) Cutting Cutting Cutting Cutting Type condition 1 condition 2 Type condition 1 condition 2 Coated 46 0.18 0.15 Comparative 46 2.3* 2.5* tools 47 0.14 0.11 coated tools 47 3.7* 3.9* according 48 0.16 0.12 48 3.0* 3.2* to the 49 0.17 0.13 49 1.2* 1.4* present 50 0.17 0.15 50 2.7* 2.5* invention 51 0.13 0.10 51 3.2* 3.3* 52 0.15 0.12 52 1.4* 1.5* 53 0.08 0.07 53 1.5* 1.3* 54 0.10 0.08 54 1.3* 1.5* 55 0.11 0.09 55 4.5* 4.7* 56 0.07 0.05 56 4.1* 4.2* 57 0.09 0.09 57 3.3* 3.5* 58 0.13 0.11 58 3.9* 4.0* 59 0.16 0.12 59 2.9* 2.8* 60 0.17 0.14 60 2.4* 2.6* The * marks in the sections of the comparative coated tools and the reference coated tools denote cutting times (minutes) at which the life end was reached due to the occurrence of chipping.

From the results shown in Tables 24 and 30, toughness is improved due to strain of the crystal grains and suppression of grain boundary slipping of the crystal grains in the coated tools according to the present invention, by the predetermined average crystal grain misorientations being present in the crystal grains which have cubic structures which form the layer of a complex nitride or a complex carbonitride of Al and Ti that forms the hard coating layer, and by the inclined angles of the normal lines of the {111} planes having the predetermined inclined angle frequency distribution in the region on the side of the tool body and in the region on the side of the surface of the crystal grains. Further, it is obvious that excellent chipping resistance and fracture resistance are achieved even in a case in which the coated tools are used in a high-speed intermittent cutting in which an intermittent and impact, high load exerts on cutting edges, and as a result, excellent wear resistance is exhibited in use over a long period of time.

In contrast, it is obvious that Comparative coated tools 31 to 45 and 46 to 60 in which the predetermined average crystal grain misorientations are not present in the crystal grains which have cubic structures which formed the layer of a complex nitride or a complex carbonitrides of Al, Ti, and Me that form the hard coating layers end the life thereof in short periods of time due to the occurrence of chipping, fracture, and the like in a case in which the coated tools are used in the high-speed intermittent cutting, which is accompanied with high heat generation, in which an intermittent and impact, high load exerts on the cutting edges.

Example 5

Tool bodies A to C made of WC-based cemented carbide and a tool body D made of TiCN-based cermet with insert shapes of ISO standard SEEN1203AFSN, which was similar to that in Example 1, were respectively manufactured.

Next, a chemical vapor deposition apparatus is used on the surfaces of these tool bodies A to D

-   -   (a) to manufacture coated tools 61 to 75 according to the         present invention under the forming conditions A to J shown in         Tables 32 and 33, that is, by using a gas group A consisting of         NH₃, N₂, and H₂ a gas group B consisting of CrCl₃, AlCl₃,         Al(CH₃)₃, N₂, and H₂ and the respective gas supply methods of         performing a thermal CVD method for a predetermined period of         time using a gas supply method in which in which a reaction gas         composition (% by volume with respect to the total for the gas         group A and the gas group B) was set to satisfy NH₃: 1.0 to         1.5%, N₂: 1.0 to 2.0%, and H₂: 55 to 60% as the gas group A and         AlCl₃: 0.6 to 0.9%, CrCl₃: 0.2 to 0.3%, Al(CH₃)₃: 0 to 0.5%, N₂:         12.5 to 15.0%, and H₂: remainder under conditions of a reaction         atmosphere pressure: 4.5 to 5.0 kPa, a reaction atmosphere         temperature: 750 to 900° C., a supply cycle: 1 to 5 seconds, a         gas supply time per cycle: 0.15 to 0.25 seconds, and a supply         phase difference between the gas group A and the gas group B of         0.10 to 0.20 seconds to form hard coating layers of         (Cr_(1-p)Al_(p))(C_(q)N_(1-q)) layers, in which crystal grains         that had cubic structures with average crystal grain         misorientations of 2 degrees or greater as shown in Table 35         were present at area ratios shown in Table 35, which had target         layer thicknesses shown in Table 35.

Note that for coated tools 66 to 73 according to the present invention, lower layers shown in Table 34 and/or upper layers shown in Table 35 were formed under forming conditions shown in Table 31.

In addition, for the purpose of comparison, hard coating layers that contained at least layer of a complex nitride or a complex carbonitrides of Cr and Al with the target layer thicknesses (μm) shown in Table 36 were deposited on the surfaces of tool bodies A to D under the conditions shown in Tables 32 and 33 in a manner similar to that for coated tools 61 to 75 according to the present invention. At this time, Comparative coated tools 61 to 73 were manufactured by forming the hard coating layers such that the reaction gas composition on the surface of the tool bodies did not temporarily change in a process of forming the (Cr_(1-p)Al_(p))(C_(q)N_(1-q)) layers.

Note that the lower layers shown in Table 34 and/or the upper layers shown in Table 36 were formed for Comparative coated tools 66 to 73 in a manner similar to those for coated tools 66 to 73 according to the present invention under the forming conditions shown in Table 31.

For reference, Reference coated tools 74 and 75 shown in Table 36 were manufactured by depositing (Cr_(1-p)Al_(p))(C_(q)N_(1-q)) layers in the reference examples with target layer thicknesses on the surfaces of the tool body B and the tool body C by arc ion plating using a physical vapor deposition apparatus in the related art.

Note that conditions for the arc ion plating used in the vapor deposition in the reference examples were as follows.

(a) Aforementioned tool bodies B and C were ultrasonically washed in acetone and were attached to a rotation table in an arc ion plating apparatus along an outer circumferential portion at a position away from the center axis by a predetermined distance in a radial direction in a dried state, and an Al—Cr alloy with a predetermined composition was deployed for a cathode electrode (evaporation source).

(b) First, the inside of the apparatus was evacuated and was heated to 500° C. with a heater while being maintained at a vacuum of 10⁻² Pa or lower, a DC bias voltage of −1000V was then applied to the tool bodies that rotated while revolving on the aforementioned rotation table, a current of 200 A was caused to flow between the cathode electrode made of the Al—Cr alloy and an anode electrode to cause arc discharge and generate Al ions and Cr ions in the apparatus, and thereafter, the surfaces of the tool bodies were treated by bombard cleaning.

(c) Then, nitrogen gas was introduced as reaction gas into the apparatus to obtain a reaction atmosphere at 4 Pa, a DC bias voltage at −50 V was applied to the tool bodies that rotated while revolving on the rotation table, and a current of 120 A was caused to flow between the cathode electrode (evaporation source) made of the Al—Cr alloy and the anode electrode to cause arc discharge.

In addition, a scanning electron microscope (magnification: 5000 times) was used to measure sections in a direction perpendicular to the tool bodies of the respective constituent layers of coated tools 61 to 75 according to the present invention, Comparative coated tools 61 to 73, and Reference coated tools 74 and 75, and layer thicknesses at five points in an observation field of view were measured and averaged to obtain average layer thicknesses. All the layers had average layer thicknesses that were substantially the same as the target layer thicknesses shown in Tables 34 to 36.

In addition, for the average content ratio p_(avg) of Al in the layer of a complex nitride or a complex carbonitride, the average content ratio p_(avg) of Al was obtained from averages of obtained analysis results of characteristic X-rays at ten points by irradiating polished surface as a surfaces of the samples with electron beams from the side of the surfaces of the samples by using an electron microanalyzer (EPMA). The average content ratio q_(avg) of C was obtained by secondary ion mass analysis (SIMS). The ranges of 70 μm×70 μm from the side of the surfaces of the samples were irradiated with ion beams, and concentrations of the components discharged by a sputtering effect were measured in a depth direction. The average content ratio q_(avg) of C represents an average value in the depth direction of the layer of a complex nitride or a complex carbonitride of Cr and Al. However, the content ratio of C excludes a content ratio of inevitable C contained even when gas containing C is intentionally not used as a gas raw material. Specifically, the content ratio (atomic ratio) of the C component contained in the layer of a complex nitride or a complex carbonitride in a case in which the supply amount of Al(CH₃)₃ is assumed to be 0 was obtained as the content ratio of inevitable C, and a value obtained by subtracting the content ratio of inevitable C from a content ratio (atomic ratio) of the C component contained in the layer of a complex nitride or a complex carbonitride obtained in a case in which Al(CH₃)₃ was intentionally supplied was obtained as q_(avg).

Furthermore, crystal orientations of the individual crystal grains which had cubic structures that formed the layer of a complex nitride or a complex carbonitride of Cr and Al were analyzed in the vertical sectional direction by using an electron backscatter diffraction apparatus, and in a case in which there were misorientations of 5 degrees or greater between adjacent pixels, the parts were regarded as grain boundaries, a region surrounded by grain boundaries was regarded as one crystal grain, crystal grain misorientations were obtained between a certain pixel in a crystal grain and all the other pixels in the same crystal grain, and the crystal grain misorientations were mapped by dividing a range of 0 to 10 degrees into sections of each 1 degree, that is, a section of equal to or greater than 0 degrees and less than 1 degree, a section of equal to or greater than 1 degree and less than 2 degrees, a section of equal to or greater than 2 degrees and less than 3 degrees, a section of equal to or greater than 3 degrees and less than 4 degrees, and the like. The area ratio of the crystal grains with the average crystal grain misorientations of 2 degrees or greater with respect to the entire layer of a complex nitride or a complex carbonitride of Cr and Al was obtained from the mapping diagram. The results are shown in Tables 35 and 36.

FIG. 11 shows an example of histogram of the average crystal grain misorientations (that is, GOS values) measured in the coated tool 18 according to the present invention, and FIG. 12 shows an example of histogram of the average crystal grain misorientations measured in the comparative coated tool 9.

In addition, for inclined angle frequency distribution of the hard coating layer, a section of the hard coating layer formed of the layer of the complex carbonitride of Cr and Al that had cubic structures was placed in a body tube of a field emission-type scanning electron microscope in a state in which the section was polished, the polished surface as a surface was analyzed in a region on the side of the surface (boundary surface) of the tool body and a region on the side of the surface, which were obtained by equally dividing the polished surface as a surface into two regions in the layer thickness direction, the individual crystal grains that had cubic crystal grain lattice that was present within the measurement ranges were irradiated with electron beams at an acceleration voltage of 10 kV at an incident angle of 70 degrees with an irradiation current of 1 nA, within the measurement ranges of the region on the side of the tool body and the region on the side of the surface in the direction perpendicular to the tool body, and for the width of 10 μm for five fields of view at intervals of 0.1 μm/step in the horizontal direction of the tool body, inclined angles of normal lines of {111} planes, which were crystal planes of the crystal grains, with respect to a normal line of the surface of the tool body (a direction perpendicular to the surface of the tool body in the polished section) were measured by using an electron backscatter diffraction image apparatus, measured inclined angles within a range of 0 to 45 degrees from among the measured inclined angles were divided into sections at a pitch of 0.25 degrees on the basis of the measurement results, and a ratio of the frequencies at which the measured inclined angles were present within a range of 0 to 12 degrees being obtained by aggregating the frequencies at which the measured inclined angles were present. The results are shown in Tables 35 and 36.

FIG. 13 shows an example of the inclined angle frequency distribution measured in the region on the side of the tool body of the hard coating layer that is formed of the layer of the complex carbonitride of Cr and Al of the coated tool according to the present invention, and FIG. 14 shows an example of the inclined angle frequency distribution measured in the region on the side of the surface of the hard coating layer that is formed of the layer of complex carbonitride of Cr and Al of the coated tool according to the present invention.

Further, analysis was performed at intervals of 0.1 μm in the vertical sectional direction by using an electron backscatter diffraction apparatus, measurement within a measurement range with a width of 10 μm and a vertical length of the film thickness in the vertical sectional direction was performed in five fields of view, the total number of pixels that belonged to the crystal grains that formed the layer of a complex nitride or a complex carbonitride was obtained, and the area ratio of the crystal grains which had cubic structures that had the layer of a complex nitride or a complex carbonitride and had the cubic structures was obtained from a ratio with respect to the total number of measured pixels in the measurement performed on the hard coating layer in the aforementioned five fields of view.

TABLE 31 Forming conditions (pressure of reaction atmosphere indicates Constituent layer of hard coating layer kPa and temperature indicates ° C.)Forming conditions Formation Reaction atmosphere Type symbol Reaction gas composition (% by volume) Pressure Temperature (Cr_(1−p)Al_(p))(C_(q)N_(1−q)) CrAlCN CrAlCN See Table 32. See Table 33. See Table 33. layer Ti compound TiC TiC TiCl₄: 4.2%, CH₄: 8.5%, H₂: remainder 7 900 layer TiN TiN-1 TiCl₄: 4.2%, N₂: 30%, H₂: remainder 30 850 TiN-2 TiCl₄: 4.2%, N₂: 35%, H₂: remainder 50 900 1-TiCN 1-TiCN TiCl₄: 2%, CH₃CN: 0.7%, N₂: 10%, H₂: remainder 7 900 TiCN TiCN TiCl₄: 2%, CH₄: 1%, N₂: 15%, H₂: remainder 13 900 TiCO TiCO TiCl₄: 4.2%, CO: 4%, H₂: remainder 7 900 TiCNO TiCNO TiCl₄: 2%, CO: 1%, CH₄: 1%, N₂: 5%, H₂: remainder 13 900 Al₂O₃ layer Al₂O₃ Al₂O₃ AlCl₃: 2.2%, CO₂: 5.5%, HCl: 2.2%, H₂S: 0.2%, H₂: remainder 7 900

TABLE 32 Formation of hard Forming conditions (reaction gas composition is represented as coating layer ratio with respect to a total for the gas group A and the gas group B.) Process Formation Reaction gas group A Reaction gas group B type symbol composition (% by volume) composition (% by volume) Film A NH₃: 1.0% N₂: 1.0% H₂: 60% AlCl₃: 0.8% CrCl₃: 0.3% N₂: 13% Al(CH₃)₃: 0% H₂: remainder forming B NH₃: 1.5% N₂: 2.0% H₂: 55% AlCl₃: 0.6% CrCl₃: 0.2% N₂: 12.5% Al(CH₃)₃: 0% H₂: remainder process C NH₃: 1.5% N₂: 2.0% H₂: 60% AlCl₃: 0.9% CrCl₃: 0.2% N₂: 12.8% Al(CH₃)₃: 0% H₂: remainder according D NH₃: 1.0% N₂: 1.0% H₂: 55% AlCl₃: 0.9% CrCl₃: 0.3% N₂: 14% Al(CH₃)₃: 0.5% H₂: remainder to the E NH₃: 1.5% N₂: 1.0% H₂: 55% AlCl₃: 0.7% CrCl₃: 0.2% N₂: 13% Al(CH₃)₃: 0% H₂: remainder present F NH₃: 1.0% N₂: 1.0% H₂: 60% AlCl₃: 0.8% CrCl₃: 0.3% N₂: 14% Al(CH₃)₃: 0% H₂: remainder invention G NH₃: 1.0% N₂: 1.0% H₂: 55% AlCl₃: 0.6% CrCl₃: 0.3% N₂: 13.5% Al(CH₃)₃: 0.4% H₂: remainder H NH₃: 1.5% N₂: 1.0% H₂: 55% AlCl₃: 0.7% CrCl₃: 0.3% N₂: 14.5% Al(CH₃)₃: 0.2% H₂: remainder I NH₃: 1.0% N₂: 2.0% H₂: 60% AlCl₃: 0.6% CrCl₃: 0.2% N₂: 13.5% Al(CH₃)₃: 0% H₂: remainder J NH₃: 1.5% N₂: 2.0% H₂: 60% AlCl₃: 0.7% CrCl₃: 0.3% N₂: 15% Al(CH₃)₃: 0% H₂: remainder Compar- A′ NH₃: 1.0% N₂: 1.0% H₂: 60% AlCl₃: 0.8% CrCl₃: 0.3% N₂: 13% Al(CH₃)₃: 0% H₂: remainder ative B′ NH₃: 1.5% N₂: 2.0% H₂: 55% AlCl₃: 0.6% CrCl₃: 0.2% N₂: 12.5% Al(CH₃)₃: 0% H₂: remainder film C′ NH₃: 1.5% N₂: 2.0% H₂: 60% AlCl₃: 0.9% CrCl₃: 0.2% N₂: 12.8% Al(CH₃)₃: 0% H₂: remainder forming D′ NH₃: 1.0% N₂: 1.0% H₂: 55% AlCl₃: 0.9% CrCl₃: 0.3% N₂: 14% Al(CH₃)₃: 0.5% H₂: remainder process E′ NH₃: 1.5% N₂: 1.0% H₂: 55% AlCl₃: 0.7% CrCl₃: 0.2% N₂: 13% Al(CH₃)₃: 0% H₂: remainder F′ NH₃: 1.0% N₂: 1.0% H₂: 60% AlCl₃: 0.8% CrCl₃: 0.3% N₂: 14% Al(CH₃)₃: 0% H₂: remainder G′ NH₃: 1.0% N₂: 1.0% H₂: 55% AlCl₃: 0.6% CrCl₃: 0.3% N₂: 13.5% Al(CH₃)₃: 0.4% H₂: remainder H′ NH₃: 1.5% N₂: 1.0% H₂: 55% AlCl₃: 0.7% CrCl₃: 0.3% N₂: 14.5% Al(CH₃)₃: 0.2% H₂: remainder I′ NH₃: 1.0% N₂: 1.0% H₂: 60% AlCl₃: 0.6% CrCl₃: 0.2% N₂: 13.5% Al(CH₃)₃: 0% H₂: remainder J′ NH₃: 1.5% N₂: 2.0% H₂: 60% AlCl₃: 0.7% CrCl₃: 0.3% N₂: 15% Al(CH₃)₃: 0% H₂: remainder

TABLE 33 Forming conditions (pressure of reaction atmosphere indicates kPa and temperature indicates ° C.) Forming conditions Phase difference in supply Gas group A Gas group B between Formation of hard Supply Supply gas group coating layer Supply time per Supply time per A and gas Formation cycle cycle cycle cycle group B Reaction atmosphere Process type symbol (seconds) (seconds) (seconds) (seconds) (seconds) Pressure Temperature Film A 4 0.2 4 0.2 0.1 5 850 forming B 5 0.2 5 0.2 0.15 4.7 800 process C 1.2 0.25 1.2 0.25 0.2 4.7 900 according to D 2 0.25 2 0.25 0.15 5 750 the present E 1 0.2 1 0.2 0.15 4.7 800 invention F 2.5 0.2 2.5 0.2 0.1 4.7 750 G 4.5 0.2 4.5 0.2 0.1 4.7 800 H 2.5 0.2 2.5 0.2 0.15 4.5 800 I 1.5 0.15 1.5 0.15 0.1 4.7 750 J 3 0.15 3 0.15 0.1 4.5 800 Comparative A′ — — — — — 5 850 film forming B′ — — — — — 4.7 800 process C′ — — — — — 4.7 900 D′ — — — — — 5 750 E′ — — — — — 4.7 800 F′ — — — — — 4.7 750 G′ — — — — — 4.7 800 H′ — — — — — 4.5 800 I′ — — — — — 4.7 750 J′ — — — — — 4.5 800

TABLE 34 Hard coating layer (Numerical values in the lower sections represent target average layer thickness (μm) of the layer. Lower layer Tool body First Second Third Type symbol layer layer layer Coated tools 61 A — — — according to 62 B — — — the present 63 C — — — invention/ 64 D — — — Comparative 65 A — — — coated tools/ 66 B TiC — — Reference (0.5) coated tools 67 C TiN-1 — — (0.3) 68 D TiN-1 1-TiCN — (0.5) (4) 69 A TiN-1 1-TiCN TiCN (0.3) (2) (0.7) 70 B — — — 71 C TiN-1 — — (0.5) 72 D TiC — — (1)   73 A TiN-1 — — (0.1) 74 B — — — 75 C — — —

TABLE 35 Hard coating layer CrAl complex carbide or carbonitride layer (Cr_(1−p)Al_(p))(C_(q)N_(1−q)) Area ratio of crystal grains Formation having symbol of average process of crystal grain Average forming misorientation crystal grain Tool CrAlCN Content equal to or Area ratio width W of body (See Tables ratio x_(avg) of Content ratio greater than 2 of cubic crystal Type symbol 4 and 5) Al of y_(avg) of C degrees (%) crystal (%) grains (μm) Coated tools 61 A A 0.74 0.0001 or less 41 100 1.1 according to 62 B B 0.82 0.0001 or less 51 100 1.1 the present 63 C C 0.93 0.0001 or less 35 89 0.6 invention 64 D D 0.95 0.0042 35 65 0.1 65 A E 0.93 0.0001 or less 42 99 0.8 66 B F 0.74 0.0001 or less 36 100 0.8 67 C G 0.89 0.0035 20 100 0.2 68 D H 0.83 0.0013 63 100 0.5 69 A I 0.79 0.0001 or less 30 100 0.4 70 B J 0.70 0.0001 or less 54 100 0.30 71 C A 0.75 0.0001 or less 39 100 0.9 72 D B 0.81 0.0001 or less 58 100 1.3 73 A C 0.92 0.0001 or less 38 92 1.2 74 B D 0.94 0.0041 39 72 0.5 75 C E 0.92 0.0001 or less 38 96 1.1 Hard coating layer CrAl complex carbide or carbonitride layer (Cr_(1−p)Al_(p))(C_(q)N_(1−q)) Distribution Distribution ratio of ratio of frequencies frequencies at which at which inclined inclined angles of angles of normal lines normal lines Inclined of {111} of {111} angle planes are planes are section in present in a present in a which the range of 0 range of 0 highest peak Upper layer to 12 to 12 is observed (Numerical values in the degrees in degrees in in the region lower sections represent Average the region the region on the side target average layer aspect ratio on the side on the side of the Target layer thicknesses (μm) of the A of crystal of the tool of the surface thickness layers.) Type grains body M_(deg) surface N_(deg) (degrees) (μm) First layer Second layer Coated tools 61 1.5 32 54 7.75 to 8.00 6 — — according to 62 2.1 28 56 4.75 to 5.00 4 — — the present 63 2.6 25 48 3.00 to 3.25 4.5 — — invention 64 3.1 40 61 4.25 to 4.50 2.5 — — 65 4.7 15 30 5.25 to 5.50 5 — — 66 2.3 16 39 9.00 to 9.25 3.5 — — 67 3.2 21 40 6.00 to 6.25 2 — — 68 2.2 28 45 4.50 to 4.75 3 — — 69 8.5 10 39 8.50 to 8.75 7 — — 70 1.5 31 52 6.75 to 7.00 4 Al₂O₃ — (2.5) 71 2.4 25 44 5.50 to 5.75 3 TiCN Al₂O₃ (0.5) (3) 72 2.8 29 59 4.25 to 4.50 5 TiCO Al₂O₃ (1) (2) 73 3.8 31 45 3.50 to 3.75 6 TiCNO Al₂O₃ (0.3) (1) 74 4.2 40 63 5.00 to 5.25 7 — — 75 3.1 17 29 4.50 to 4.75 8 — —

TABLE 36 Hard coating layer CrAl complex carbide or carbonitride layer (Cr_(1−p)Al_(p))(C_(q)N_(1−q)) Area ratio of crystal grains Formation having symbol of average Average process of crystal grain crystal forming misorientation grain width Tool CrAlCN Content equal to or Area ratio W of body (See Tables ratio x_(avg) of Content ratio greater than 2 of cubic crystal Type symbol 4 and 5) Al of y_(avg) of C degrees (%) crystal (%) grains (μm) Comparative 61 A A′ 0.76 0.0001 or 4 98 0.9 coated tools less 62 B B′ 0.83 0.0001 or 9 93 0.8 less 63 C C′ 0.91 0.0001 or 6 91 0.4 less 64 D D′ 0.94 0.0039 6 81 0.2 65 A E′ 0.91 0.0001 or 7 97 0.7 less 66 B F′ 0.73 0.0001 or 4 100 0.8 less 67 C G′ 0.88 0.0023 0 96 0.2 68 D H′ 0.81 0.0022 4 100 0.4 69 A I′ 0.77 0.0001 or 13 100 0.4 less 70 B J′ 0.71 0.0001 or 5 100 0.40 less 71 C A′ 0.78 0.0001 or 8 98 0.8 less 72 D B′ 0.81 0.0001 or 6 92 0.7 less 73 A C′ 0.94 0.0001 or 5 93 1.1 less Reference coated 74 B AIP 0.69 0.0001 or 14 100 1.4 tools less 75 C AIP 0.59 0.0001 or 11 100 0.7 less Hard coating layer CrAl complex carbide or carbonitride layer (Cr_(1−p)Al_(p))(C_(q)N_(1−q)) Distribution Distribution ratio of ratio of frequencies frequencies at which at which inclined inclined angles of angles of normal normal lines of lines of {111} {111} planes are planes are Upper layer present in a present in a (Numerical values range of 0 range of 0 Inclined angle in the lower to 12 to 12 section in which sections represent degrees in degrees in the highest peak target average Average the region the region is observed in Target layer thicknesses aspect ratio on the side on the side the region on the layer (μm) of the layers.) A of crystal of the tool of the side of the thickness First Type grains body M_(deg) surface N_(deg) surface (degrees) (μm) layer Second layer Comparative 61 2.5 34 43 23.25 to 23.50 6 — — coated tools 62 1.5 33 37 21.25 to 21.50 4 — — 63 2.2 26 32 28.25 to 28.50 4.5 — — 64 2.6 34 28 18.25 to 18.50 2.5 — — 65 4.8 25 32 35.00 to 35.25 5 — — 66 2.6 19 22 28.25 to 28.50 3.5 — — 67 3.1 27 22 32.75 to 33.00 2 — — 68 1.9 22 25 31.00 to 31.25 3 — — 69 7.6 24 21 26.75 to 27.00 7 — — 70 2.1 24 28 23.25 to 23.50 4 Al₂O₃ — (2.5) 71 1.9 32 41 25.50 to 25.75 3 TiCN Al₂O₃ (0.5) (3) 72 2.4 26 34 17.25 to 17.50 5 TiCO Al₂O₃ (1) (2) 73 3.5 35 28 41.50 to 41.75 6 TiCNO Al₂O₃ (0.3) (1) Reference coated 74 3.3 27 32 28.25 to 28.50 7 — — tools 75 2.8 25 31 30.25 to 30.50 6 — — (Note) “AIP” indicates a film formed through arc ion plating.

Next, all the aforementioned variety of coated tools, namely coated tools 61 to 75 according to the present invention, Comparative coated tools 61 to 73, and Reference coated tools 74 and 75 were subjected to the following dry high-speed face milling and a center cutting machining test, which are types of high-speed intermittent cutting of carbon steel, in a state in which the coated tools were clamped with fixing jigs at tip ends of cutters made of tool steel with a cutter diameter of 125 mm, and wear width of a flank faces at all the cutting edges were measured. The results are shown in Table 37.

Tool body: tungsten-carbide-based cemented carbide, titanium-carbonitride-based cermet Cutting test: dry high-speed face milling, center cutting machining

Work material: block material of JIS⋅S55C with a width of 100 mm and a length of 400 mm

Rotation speed: 713 min⁻¹

Cutting speed: 280 m/min

Depth of cut: 2.5 mm

Feed rate per tooth: 0.25 mm/tooth

Cutting time: 8 minutes

TABLE 37 Wear width Cutting of a flank test result Type face (mm) Type (minutes) Coated tools 61 0.13 Comparative 61 2.3* according to 62 0.07 coated 62 3.7* the present 63 0.08 tools 63 3.1* invention 64 0.14 64 2.0* 65 0.09 65 4.2* 66 0.08 66 4.2* 67 0.10 67 4.0* 68 0.11 68 1.9* 69 0.08 69 4.4* 70 0.13 70 2.5* 71 0.12 71 2.1* 72 0.07 72 4.4* 73 0.10 73 4.3* 74 0.09 Reference 74 3.8* 75 0.12 coated tools 75 2.8* The * marks in the sections of the comparative coated tools and the reference coated tools denote cutting times (minutes) at which life end was reached due to the occurrence of chipping.

Example 6

Tool bodies α to γ made of WC-based cemented carbide and a tool body δ made of TiCN-based cermet with insert shapes of ISO standard SEEN1203AFSN, which was similar to that in Example 2, were respectively manufactured.

Next, coated tools 76 to 90 according to the present invention shown in Table 39 were manufactured by using a chemical vapor deposition apparatus on the surfaces of these tool bodies α to γ and the tool body δ to deposit hard coating layers with target layer thicknesses, which included at least (Cr_(1-p)Al_(p))(C_(q)N_(1-q)), under the conditions shown in Tables 32 and 33 by a method similar to that in Example 5.

Note that the lower layers shown in Table 38 and/or the upper layers shown in Table 39 were formed for coated tools 79 to 88 according to the present invention under the forming conditions shown in Table 31.

In addition, for the purpose of comparison, Comparative coated tools 76 to 88 shown in Table 40 were similarly manufactured by using an ordinary chemical vapor deposition apparatus on the surfaces of these tool bodies α to γ and the tool body δ to deposit hard coating layers with target layer thicknesses shown in Table 40 under the conditions shown in Tables 32 and 33 in a manner similar to that for the coated tools according to the present invention.

Note that the lower layers shown in Table 38 and/or the upper layers shown in Table 40 were formed for Comparative coated tools 79 to 88 under the forming conditions shown in Table 31 in a manner similar to that for coated tools 79 to 88 according to the present invention.

For reference, Reference coated tools 89 and 90 shown in Table 40 were manufactured by depositing (Cr_(1-p)Al_(p))(C_(q)N_(1-q)) layers in the reference examples with target layer thicknesses on the surfaces of the tool body β and the tool body γ by arc ion plating using a physical vapor deposition apparatus in the related art.

Note that conditions similar to the conditions shown in Example 5 were used as conditions for the arc ion plating.

In addition, a scanning electron microscope (magnification: 5000 times) was used to measure sections of the respective constituent layers of coated tools 76 to 90 according to the present invention, Comparative coated tools 76 to 88, and Reference coated tools 89 and 90, and layer thicknesses at five points in an observation field of view were measured and averaged to obtain average layer thicknesses. All the layers had average layer thicknesses that were substantially the same as the target layer thicknesses shown in Tables 39 to 40.

Furthermore, crystal orientations of the individual crystal grains which had cubic structures that formed the layer of a complex nitride or a complex carbonitride of Cr and Al were analyzed in the vertical sectional direction by using an electron backscatter diffraction apparatus, and crystal grain misorientations were mapped by dividing a range of 0 to 10 degrees into sections of each 1 degree, that is, a section of equal to or greater than 0 degrees and less than 1 degree, a section of equal to or greater than 1 degree and less than 2 degrees, a section of equal to or greater than 2 degrees and less than 3 degrees, a section of equal to or greater than 3 degrees and less than 4 degrees, and the like. Average crystal grain misorientations and an area ratio of the crystal grains with the average crystal grain misorientations of 2 degrees or greater with respect to the entire layer of a complex nitride or a complex carbonitride of Cr and Al were obtained from the mapping diagram. The results are shown in Tables 39 and 40.

In addition, for inclined angle frequency distribution of the hard coating layer, a section of the hard coating layer formed of the layer of the complex carbonitride of Cr and Al that had cubic structures was placed in a body tube of a field emission-type scanning electron microscope in a state in which the section was polished, the polished surface as a surface was analyzed in a region on the side of the surface (boundary surface) of the tool body and a region on the side of the surface, which were obtained by equally dividing the polished surface as a surface into two regions in the layer thickness direction, the individual crystal grains that had cubic crystal grain lattice that was present within measurement ranges in the region on the side of the tool body and in the region on the side of the surface were irradiated with electron beams at an acceleration voltage of 10 kV at an incident angle of 70 degrees with an irradiation current of 1 nA, inclined angles of normal lines of {111} planes, which were crystal planes of the crystal grains, with respect to a normal line of the surface of the tool body (a direction perpendicular to the surface of the tool body in the polished section) were measured for the width of 10 μm for five fields of view at intervals of 0.1 μm/step in the horizontal direction of the tool body by using an electron backscatter diffraction image apparatus, measured inclined angles within a range of 0 to 45 degrees from among the measured inclined angles were divided into sections at a pitch of 0.25 degrees on the basis of the measurement results, and frequencies at which the measured inclined angles were present in the respective sections were aggregated, thereby a ratio of frequencies at which the measured inclined angles were present within a range of 0 to 12 degrees being obtained. The results are shown in Tables 39 and 40.

TABLE 38 Hard coating layer (Numerical values in the lower sections represent target average layer thickness (μm) of the layer.) Lower layer Tool body Fourth Type symbol First layer Second layer Third layer layer Coated tools according 76 α — — — — to the present 77 β — — — — invention/Comparative 78 γ — — — — coated tools/Reference 79 δ TiC — — — coated tools (0.5) 80 α TiN-1 — — — (0.1) 81 β TiN-1 1-TiCN — — (0.5) (7) 82 γ TiN-1 1-TiCN TiN-2 — (0.3) (10)  (0.7) 83 δ TiN-1 1-TiCN TiCN TiN-2 (0.3) (4) (0.4) (0.3) 84 α — — — — 85 β TiN-1 — — (0.5) 86 γ TiC — — (1) 87 δ TiN-1 — — (0.1) 88 α TiN-1 — — (0.1) 89 β — — — 90 γ — — —

TABLE 39 Hard coating layer CrAl complex carbide, carbonitride layer (Cr_(1−p)Alp)(C_(q)N_(1−q)) Formation symbol of process of Average forming Area ratio of crystal crystal CrAlCN grains having average grain Average (See crystal grain width W aspect Tool Tables 4 misorientation equal to Area ratio of of crystal ratio A of body and Content ratio Content ratio or greater than 2 cubic crystal grains crystal Type symbol 5) x_(avg) of Al of y_(avg) of C degrees (%) (%) (μm) grains Coated 76 α A 0.75 0.0001 or 28 97 2.0 5.6 tools less according 77 β B 0.80 0.0001 or 59 98 1.8 5.8 to the less present 78 γ C 0.94 0.0001 or 46 96 1.8 5.9 invention less 79 δ D 0.93 0.0041 44 79 0.6 4.8 80 α E 0.91 0.0001 or 24 93 0.4 10.0 less 81 β F 0.75 0.0001 or 39 100 0.9 3.2 less 82 γ G 0.87 0.0033 55 95 0.7 2.1 83 δ H 0.82 0.0021 33 100 1.2 4.2 84 α I 0.77 0.0001 or 48 98 1.4 10.0 less 85 β J 0.72 0.0001 or 51 100 0.5 2.0 less 86 γ A 0.78 0.0001 or 31 97 1.2 3.2 less 87 δ B 0.82 0.0001 or 61 96 1.7 8.2 less 88 α C 0.93 0.0001 or 42 95 1.2 2.1 less 89 β D 0.95 0.0037 42 81 0.5 5.3 90 γ E 0.90 0.0001 or 22 96 0.7 8.6 less Hard coating layer CrAl complex carbide, carbonitride layer (Cr_(1−p)Alp)(C_(q)N_(1−q)) Distribution Distribution ratio of ratio of frequencies at frequencies at which inclined which inclined angles of angles of Inclined normal lines of normal lines of angle section {111} planes {111} planes in which the are present in a are present in a highest peak Upper layer (Numerical range of 0 to range of 0 to is observed in values in the lower sections represent 12 degrees in 12 degrees in the region on target average layer thicknesses the region on the region on the side of Target layer (μm) of the layer.) the side of the the side of the the surface thickness First Second Third Fourth Type tool body M_(deg) surface N_(deg) (degrees) (μm) layer layer layer layer Coated 76 38 49 11.75 to 16 — — — — tools 12.00 according 77 38 67 5.25 to 5.50 12 — — — — to the present 78 33 55 4.75 to 5.00 15 — — — — invention 79 40 61 3.75 to 4.00 7 — — — — 80 10 38 10.00 to 6 — — — — 10.25 81 24 44 3.50 to 3.75 7 — — — — 82 29 56 2.75 to 3.00 3 TiN-2 — — — (0.7) 83 16 30 3.75 to 4.00 8 TiCN TiN-2 — — (0.4) (0.3) 84 21 49 7.25 to 7.50 20 Al₂O₃ — — — (2) 85 29 59 5.75 to 6.00 4 TiCN Al₂O₃ — — (0.5) (2.5) 86 36 52 8.75 to 9.00 5 TiCO Al₂O₃ — — (1) (2) 87 40 70 4.50 to 4.75 16 TiCNO Al₂O₃ — — (0.3) (1) 88 36 52 6.00 to 6.25 4 TiN-2 TiCN TiCNO Al₂O₃ (0.3) (0.8) (0.3) (3) 89 38 59 2.00 to 2.25 9 — — — — 90 15 42 6.00 to 6.25 11 — — — —

TABLE 40 Hard coating layer CrAl complex carbide, carbonitride layer (Cr_(1−p)Alp)(C_(q)N_(1−q)) Formation symbol of process of Average forming Area ratio of crystal crystal CrAlCN grains having average grain Average (See crystal grain width W aspect Tool Tables 4 misorientation equal to Area ratio of of crystal ratio A of body and Content ratio Content ratio or greater than 2 cubic crystal grains crystal Type symbol 5) x_(avg) of Al of y_(avg) of C degrees (%) (%) (μm) grains Comparative 76 α A′ 0.76 0.0001 or 3 100 2.0 4.8 coated less tools 77 β B′ 0.83 0.0001 or 6 100 1.6 6.8 less 78 γ C′ 0.92 0.0001 or 4 96 1.7 5.4 less 79 δ D′ 0.95 0.0038 1 78 0.7 3.9 80 α E′ 0.90 0.0001 or 6 99 0.6 7.3 less 81 β F′ 0.74 0.0001 or 4 100 0.8 4.2 less 82 γ G′ 0.90 0.0029 10 94 0.4 2.2 83 δ H′ 0.83 0.0017 5 100 1.3 3.8 84 α I′ 0.79 0.0001 or 5 95 1.3 8.9 less 85 β J′ 0.69 0.0001 or 6 100 0.3 1.9 less 86 γ A′ 0.74 0.0001 or 6 100 1.1 2.8 less 87 δ B′ 0.79 0.0001 or 7 98 1.5 7.3 less 88 α C′ 0.91 0.0001 or 7 91 0.80 2.6 less Reference 89 β AIP 0.70 0.0001 or 12 100 1.5 3.3 coated less tools 90 γ AIP 0.60 0.0001 or 13 100 1.6 5.1 less Hard coating layer CrAl complex carbide, carbonitride layer (Cr_(1−p)Alp)(C_(q)N_(1−q)) Distribution Distribution ratio of ratio of frequencies at frequencies at which inclined which inclined angles of angles of Inclined normal lines of normal lines of angle section {111} planes {111} planes in which the are present in a are present in a highest peak Upper layer (Numerical values range of 0 to range of 0 to is observed in in the lower sections represent 12 degrees in 12 degrees in the region on target average layer thicknesses the region on the region on the side of Target layer (μm) of the layer.) the side of the the side of the the surface thickness First Second Third Fourth Type tool body M_(deg) surface N_(deg) (degrees) (μm) layer layer layer layer Comparative 76 18 23 32.00 to 16 — — — — coated 32.25 tools 77 29 36 32.25 to 12 — — — — 32.50 78 27 22 33.25 to 15 — — — — 33.50 79 26 22 15.25 to 7 — — — — 15.50 80 34 43 24.50 to 6 — — — — 24.75 81 15 18 33.25 to 7 — — — — 33.50 82 24 19 26.75 to 3 TiN-2 — — — 27.00 (0.7) 83 31 28 34.25 to 8 TiCN TiN-2 — — 34.50 (0.4) (0.3) 84 23 18 42.50 to 20 Al₂O₃ — — — 42.75 (2) 85 26 31 32.00 to 4 TiCN Al₂O₃ — — 32.25 (0.5) (2.5) 86 21 25 29.25 to 5 TiCO Al₂O₃ — — 29.50 (1) (2) 87 25 31 27.25 to 16 TiCNO Al₂O₃ — — 27.50 (0.3) (1) 88 31 27 36.75 to 4 TiN-2 TiCN TiCNO Al₂O₃ 37.00 (0.3) (0.8) (0.3) (3) Reference 89 26 33 31.75 to 9 — — — — coated 32.00 tools 90 28 36 29.25 to 11 — — — — 29.50 (Note) “AIP” indicates a film formed through arc ion plating.

Next, all the aforementioned variety of coated tools, namely coated tools 76 to 90 according to the present invention, Comparative coated tools 76 to 88, and Reference coated tools 89 and 90 were subjected to the following dry high-speed intermittent cutting test of carbon steel and a wet high-speed intermittent cutting test of ductile cast iron in a state in which the coated tools were screw-fixed with fixing jigs at tip ends of cutting tools made of tool steel, and wear width of a flank faces at all the cutting edges were measured.

Cutting condition 1:

Work material: round bar of JIS⋅S15C with four longitudinal grooves at an equal interval in a length direction

Cutting speed: 290 m/min

Depth of cut: 2.5 mm

Feed: 0.32 mm/rev

Cutting time: 5 minutes

(The ordinary cutting speed is 220 m/min)

Cutting condition 2:

Work material: round bar of JIS⋅FCD450 with four longitudinal grooves at an equal interval in a length direction

Cutting speed: 270 m/min

Depth of cut: 2.0 mm

Feed: 0.32 mm/rev

Cutting time: 5 minutes

(The ordinary cutting speed is 200 m/min)

Table 41 shows results of the cutting test.

TABLE 41 Wear width of a Cutting test result flank face (mm) (minutes) Cutting Cutting Cutting Cutting Type condition 1 condition 2 Type condition 1 condition 2 Coated tools 76 0.21 0.23 Comparative coated 76 4.0* 2.4* according to 77 0.10 0.12 tools 77 4.7* 3.5* the present 78 0.19 0.10 78 2.3* 4.3* invention 79 0.22 0.14 79 2.4* 3.9* 80 0.18 0.20 80 4.4* 2.7* 81 0.13 0.11 81 4.5* 3.0* 82 0.19 0.22 82 4.2* 1.8* 83 0.21 0.13 83 3.2* 4.4* 84 0.15 0.21 84 3.9* 2.4* 85 0.23 0.23 85 2.5* 1.9* 86 0.22 0.16 86 2.9* 4.1* 87 0.12 0.20 87 4.8* 4.2* 88 0.20 0.17 88 3.6* 2.5* 89 0.16 0.22 Reference coated 89 4.3* 2.3* 90 0.22 0.18 tools 90 3.4* 3.7* The * marks in sections of the comparative coated tools and the reference coated tools denote cutting times (minutes) at which life end was reached due to the occurrence of chipping.

From the results shown in Tables 37 and 41, hardness was improved due to strain of the crystal grains, and toughness is improved while high wear resistance is maintained in the coated tools according to the present invention, by the predetermined average crystal grain misorientations being present in the crystal grains which formed the layer of a complex nitride or a complex carbonitride of Al and Cr that formed the hard coating layer and which had cubic structures, and by the inclined angles of the normal lines of the {111} planes having the predetermined inclined angle frequency distribution in the region on the side of the tool body and in the region on the side of the surface of the crystal grains. Further, it was obvious that excellent chipping resistance and fracture resistance were achieved even in a case in which the coated tools were used in a high-speed intermittent cutting in which an intermittent and impact, high load exerted on cutting edges, and as a result, excellent wear resistance was exhibited in use over a long period of time.

In contrast, it was obvious that Comparative coated tools 61 to 73 and 76 to 88 and Reference coated tools 74, 75, 89, and 90 in which the predetermined average crystal grain misorientations were not present in the crystal grains which had cubic structures which formed the layer of a complex nitride or a complex carbonitrides of Al and Cr that formed the hard coating layers or in which the inclined angles of the normal lines of the {111} planes did not have the predetermined inclined angle frequency distribution in the region on the side of the tool body and in the region on the side of the surface of the crystal grains ended the life thereof in short periods of time due to the occurrence of chipping, fracture, and the like in a case in which the coated tools were used in the high-speed intermittent cutting, which was accompanied with high heat generation, in which an intermittent and impact, high load exerted on the cutting edges.

INDUSTRIAL APPLICABILITY

As described above, since the coated tool according to the present invention can be used not only in a high-speed intermittent cutting of alloy steel but also as a coated tool for a variety of work materials to be cut, and further, the coated tool exhibits excellent chipping resistance and wear resistance in use over a long period of time, the coated tool can sufficiently satisfactorily address an improvement in a performance of a cutting apparatus, and power saving, energy saving, and cost reduction for a cutting.

REFERENCE SIGNS LIST

-   P Measurement point (pixel) -   B Grain boundary -   1 Tool body -   2 Hard coating layer -   3 Layer of a complex nitride or a complex carbonitride 

The invention claimed is:
 1. A surface-coated cutting tool comprising: a hard coating layer; and a tool body that is formed of any of tungsten-carbide-based cemented carbide, titanium-carbonitride-based cermet, and cubic boron-nitride-based ultra-high-pressure sintered body, wherein the hard coating layer is formed on a surface of the tool body, (a) the hard coating layer contains at least any of a layer of a complex nitride or a complex carbonitride of Ti and Al or a layer of a complex nitride or a complex carbonitride of Ti, Al, and Me (where Me is one kind of element selected from Si, Zr, B, V, and Cr), or a layer of a complex nitride or a complex carbonitride of Cr and Al, with an average layer thickness of 2 to 20 μm, (b) the layer of a complex nitride or a complex carbonitride contains at least a phase of a complex nitride or a complex carbonitride that has an NaCl-type face-centered cubic structure, (c) in a case in which crystal orientations of crystal grains that have NaCl-type face-centered cubic structures from among crystal grains that form the layer of a complex nitride or a complex carbonitride are analyzed in a vertical sectional direction by using an electron backscatter diffraction apparatus, and average crystal grain misorientations in the individual crystal grains are obtained, crystal grains with average crystal grain misorientations of 2 degrees or more are present at an area ratio of 20% with respect to the entire area of the layer of a complex nitride or a complex carbonitride, (d) further, in a case in which inclined angles formed by normal lines of {111} planes, which are crystal planes, with respect to a normal line direction of a surface of a tool body of the crystal grains are measured in a region on a side of the tool body and a region on a side of the surface obtained by equally dividing the layer of a complex nitride or a complex carbonitride into two regions in a layer thickness direction, and frequencies at which measured inclined angles within a range of 0 to 45 degrees with respect to the normal line direction are present from among the measured inclined angles in the respective sections obtained by dividing the inclined angles into each pitch of 0.25 degrees are aggregated, in a case where a ratio of total frequencies of the presence in a range of 0 to 12 degrees with respect to the entire frequencies in inclined angle frequency distribution is set as be M_(deg), M_(deg) ranges from 10 to 40%, and in a case where a highest peak is present in an inclined angle section within a range of 0 to 12 degrees in a region on the side of the surface, and a ratio of total frequencies of the presence in the range of 0 to 12 degrees with respect to the entire frequencies in inclined angle frequency distribution is set as be N_(deg), N_(deg) is M_(deg)+10 to M_(deg)+30%.
 2. The surface-coated cutting tool according to claim 1, wherein the layer of a complex nitride or a complex carbonitride is a layer of a complex nitride or a complex carbonitride of Ti and Al, and in a case in which a composition is represented by a composition formula: (Ti_(1-x)Al_(x))(C_(y)N_(1-y)), and an average content ratio x_(avg) of Al with respect to the total amount of Ti and Al and an average content ratio y_(avg) of C with respect to the total amount of C and N (where both x_(avg) and y_(avg) are atomic ratios) in the layer of a complex nitride or a complex carbonitride satisfy 0.60≤x_(avg)≤0.95 and 0≤y_(avg)≤0.005, respectively.
 3. The surface-coated cutting tool according to claim 1, wherein the layer of a complex nitride or a complex carbonitride is layer of a complex nitride or a complex carbonitride of Ti, Al, and Me (where Me is one kind of element selected from Si, Zr, B, V, and Cr), and in a case in which a composition thereof is represented by a composition formula: (Ti_(1-α-β)Al_(α)Me_(β))(C_(γ)Ni_(1-γ)), and an average content ratio α_(avg) of Al with respect to the total amount of Ti, Al, and Me, an average content ratio β_(avg) of Me with respect to the total amount of Ti, Al, and Me, and an average content ratio γ_(avg) of C with respect to the total amount of C and N (where all of α_(avg), β_(avg), and γ_(avg) are atomic ratios) in the layer of a complex nitride or a complex carbonitride satisfy 0.60≤α_(avg), 0.005≤β_(avg)≤0.10, 0≤γ_(avg)≤0.05, and 0.605≤α_(avg)+β_(avg)≤0.95, respectively.
 4. The surface-coated cutting tool according to claim 1, wherein the layer of a complex nitride or a complex carbonitride is a layer of a complex nitride or a complex carbonitride of Cr and Al, and in a case in which a composition thereof is represented by a composition formula: (Cr_(1-p)Al_(p))(C_(q)N_(1-q)), and an average content ratio p_(avg) of Al with respect to the total amount of Cr and Al and an average content ratio q_(avg) of C with respect to the total amount of C and N (where both p_(avg) and q_(avg) are atomic ratios) in the layer of a complex nitride or a complex carbonitride satisfy 0.70≤p_(avg)≤0.95 and 0≤q_(avg)≤0.005, respectively.
 5. The surface-coated cutting tool according to claim 1, wherein the layer of a complex nitride or a complex carbonitride contains at least 70% by area or more of a phase of a complex nitride or a complex carbonitride that has an NaCl-type face-centered cubic structure.
 6. The surface-coated cutting tool according to claim 1, wherein in a case in which the layer of a complex nitride or a complex carbonitride is observed in a vertical sectional direction of the layer, the layer of a complex nitride or a complex carbonitride has a columnar structure in which an average crystal grain width W of the individual crystal grains that have NaCl-type face-centered cubic structures ranges from 0.1 to 2 μm and an average aspect ratio A ranges from 2 to
 10. 7. The surface-coated cutting tool according to claim 1, wherein a lower layer that is formed of a Ti compound layer including one layer or two or more layers from among a carbide layer, a nitride layer, a carbonitride layer, a oxycarbide layer, and a oxycarbonitride layer of Ti and that has a total average layer thickness of 0.1 to 20 μm is present between the tool body and the layer of a complex nitride or a complex carbonitride.
 8. The surface-coated cutting tool according to claim 1, wherein an upper layer that contains at least an aluminum oxide layer and has a total average layer thickness of 1 to 25 μm is formed above the layer of a complex nitride or a complex carbonitride.
 9. A method for manufacturing the surface-coated cutting tool according to claim 1, comprising a step of: forming the layer of a complex nitride or a complex carbonitride by a chemical vapor deposition method in which at least trimethyl aluminum is contained as a reaction gas component. 